Solar Snap Radiant Heat Barrier? The 128 Correct Answer

When installing attic insulation, both radiation-tight formwork with typical types of insulation and spray foam insulation can be considered. There are a number of factors to consider when choosing between these two, most notably the climate zone in which you are building. A radiant barrier is inexpensive and reflects thermal radiation to keep attics cool. Spray foam provides insulation and some soundproofing from outside noise.

Radiant Barrier Mantle

Top floors are mainly heated by radiation. The foil surfaces of radiant barriers reflect heat and prevent it from radiating into the attic. This means that the house will be more comfortable and the efficiency of the attic insulation and air conditioning will improve.

OSB Radiation Barrier Cladding can reflect up to 97% of radiation and significantly reduce attic temperatures. Norbord’s Dave Lewis: “Using a radiant barrier jacket can reduce the attic temperature by about 30°F. It is estimated that the radiative barrier will pay for itself in 1 to 2 years of energy savings, from then on it acts as a passive energy saving system that never wears out.”

This means your attic stays cooler during hot summer months and radiates less heat into your home, resulting in savings of up to 17% on your summer cooling costs. Cooler attics and more comfortable living spaces improve the efficiency of your cooling system and extend its life through shorter cycle times. Radiation barrier cladding may only cost a few hundred dollars more per home over regular cladding, and no special tools or tradesmen are required for installation. Radiant barriers only increase shingle temperature by a few degrees and do not affect shingle warranties.

Elizabeth D. Kaufman, Architect: “I have long been skeptical of radiant barrier products. I was completely surprised to find that the shell of the building I visited yesterday was 80-90 degrees inside. It was 106 outside!!!! The only possible explanation was the Norbord Solarbord decking board. The building had no ceilings, no wall insulation, and no plasterboard. The windows and doors were not sealed. The windows were low quality, double glazed, not Low-E, and faced south and west. I really expected it wouldn’t be that hot anymore when I arrived at 1:30pm. I had to insist the door stay closed to keep the ‘cool’ air in.’

Radiation protective sheathing should only be used in cool climate zones 1, 2 and 3. Radiation protective coating can only be retrofitted to existing homes when the roof is replaced. It is installed with the foil facing the attic and needs to have air space (at least ¾ inch) in front of the foil to function and of course code for the required ventilation.

Spray foam insulation

Spray foam is a great way to keep heat in your home during the winter, and increased R values ​​will also keep your attic cooler during the hotter months. In small homes where space is at a premium or in areas that are difficult to insulate, spray foam can be a good option.

Spray foam insulation offers a higher R-value per inch as well as a way to seal off your home. Spray foam insulation also helps reduce the temperature difference between the home and the attic. Adding plumbing to this space will help your heating and cooling systems work more efficiently. However, since you are air-conditioning an additional floor, you must weigh the energy savings against the cost of heating and cooling that additional space.

Spray foam is expensive and can cost you thousands of dollars compared to traditional types of insulation. It also requires trained and experienced installers as like any insulation there can be gaps and holes if the installation is not done properly. In most cases it is the installer who tells you the R-value in your home and not an independent agency.

Spray foam attached to the underside of your roof leaves no way to cool that side of the roof system. This can cause your shingles to overheat, reducing its lifespan and requiring you to have it replaced sooner. Check your shingle manufacturer’s warranties as some warranties are void or limited or require special roofing details when foam is used on the underside of the sheathing.

Spray foam insulation does not protect attics from radiant heat, but does protect it from convection and conduction. In the summertime, radiant heat contributes the most to heated attics, so spray foam insulation may not be as effective at keeping attics cool.

Combining these two insulation methods to optimize your insulation will not work. Placing materials against the foil negates the benefit of the radiation barrier and heat is simply conducted through the materials and into the attic. When it comes to hot attics, radiant heat is the primary culprit and radiant heat barriers are an effective and economical option. Both radiant barriers and spray foam offer benefits so all options should be considered including a cost benefit analysis. Also consider a third option; raised heel straps as they make room for more insulation. Using more blown cellulose or fiberglass mat can improve your R-value exponentially, giving you more bang for your buck.

How does TechShield® compare to AtticFoil®? I get this question almost every day. First, what is Techshield®? Techshield® is a roofing material – typically OSB, laminated to an aluminum foil on one side. Techshield® is manufactured by LP Building Products or Louisianna-Pacific Corporation and is probably the most popular brand of radiation barrier decking. Other brands include Norbord’s Solarboard and Georgia-Pacific’s Thermostat.

Products such as TechShield need to face an open air gap such as an attic with the foil side facing.

The main difference between Techshield® and AtticFoil® is that Techshield® is used almost exclusively for new build or whenever a roof deck is replaced. AtticFoil® is most commonly used in the attic of existing homes.

For most new build projects, I recommend using TechShield® (or another brand). The products work well, the cost of upgrading from regular OSB decking to Radiation Barrier decking is quite low and there are NO additional labor costs as Techshield® is installed like a regular OSB deck. The foil side MUST point to the attic air space (foil DOWN). If you lay the sheeting on top and then put tar paper and shingles on top, you have NO benefit.

Do they work the same? Yes and no. Techshield® works with a quality called EMISSION LEVEL. Basically, this is the ability NOT to convert energy into radiant heat. The roof terrace gets hot and would normally want to give off radiant heat both up and down. By placing the foil on the underside of the roof terrace, the ability of the terrace to radiate heat downwards is greatly reduced. This is akin to taking two HOT baked potatoes and wrapping one in foil. The foiled potato stays hotter longer because the foil reduces or slows down the amount of energy (heat) given off.

If you wrap only half of the hot potato in foil, you have something similar to TechShield®. In this case, the potato would radiate more heat up through the unfoiled area than through the foiled side. By reducing the heat emitted into the attic, this causes the attic contents (wood, insulation, frames) to become cooler. In combination with sufficient attic ventilation, the air temperature in the attic will also be significantly cooler.

AtticFoil® works off the quality of REFLEXION as there is an air space between the heat source (roof deck) and the foil. Radiant heat is STILL emitted from the roof deck but hits the liner and reflects back, keeping everything underneath the liner cooler as objects never have a chance to absorb the radiant heat coming from the roof.

Don’t worry about the roof terrace overheating – it will only rise between 2º and 10º degrees.

By bottom tacking to the rafters, you typically achieve a greater reduction in total BTUs going to the attic compared to radiant barrier coverings.

Can I make my own radiation barrier like TechShield with AtticFoil®? You can and it’s VERY easy!

Simply unroll AtticFoil® Radiant Barrier sheeting onto standard 4’x8′ OSB or plywood. Then use a hammer clamp and ¼ inch staples to pin it in place. When installed over the rafters, it protrudes like a piece of radiant barrier decking. Or if you are installing a radiation barrier for new build, you can run the sheeting over the rafters and let it “hang down” about 4-5 inches between the rafters. Through this method, the AtticFoil® will work off the reflection quality versus the emission quality of the foil. Be sure to leave a gap at the top and bottom of each rafter run to allow air to move up and out of the attic.

Disclosure: We may receive commissions for purchases made through links in this post.

Are you planning to install a radiation barrier to help insulate your home but worry it will cause problems with your WiFi, cell phone and TV reception? That’s what we’re going to talk about today. We asked the experts about the potential impact of radiant barriers on your home’s signal reception, and here’s what they have to say.

A radiant barrier would not cause problems with your WiFi, cell phone and TV signals. It’s not made of thick metal and won’t cover a large area in your home. Because of this, radio waves can still penetrate your home and give you clear reception for your devices.

Read on so we can further explain why this sheet of metal doesn’t significantly affect signal reception in your home. We also tell you how radiant barriers work, how long they last, how much it costs to have one installed on your roof and if it works without insulation. Let’s get down to business!

Radiation barriers and signal reception

Metal is used in our homes for various purposes. One such example is the foil radiation barrier used to reduce the amount of heat entering our homes. But you may have heard that metal affects radio wave signals.

The main concern here is that using metal like aluminum could affect your signal reception. If the signal is weak, you will not get a clear reception on your devices that depend on communication technology, such as B. Radio, television, mobile phones and internet connection.

That would really be a problem as you won’t be able to receive calls and text messages on your phone, watch exciting shows on TV, listen to your favorite songs on the radio, or access the internet to get the latest news and other important information. In other words, you are locked out of what is happening in the outside world.

The signals for our televisions, cell phones and WiFi are sent to us via radio waves. This is a type of electromagnetic radiation used in communications technology. They are the reason we can see images and hear sounds from these devices.

There are several ways to block radio waves in your home, but installing foil radiation barriers is not one of them. While it’s true that radio waves have a hard time penetrating metals, there are other factors that determine how effective metals are at blocking these signals.

These factors include:

The thickness of the metal – The thicker the metal used, the more effective it is at blocking radio waves. Foil radiation barriers are only 3 to 5 mils (thousandths of an inch) thick, which is insufficient to block electromagnetic signals.

Surface – Because you only install radiation barriers in certain parts of your home (most likely your ceiling or attic), there are other areas where radio wave signals can still penetrate.

Since foil radiation barriers are not thick enough and do not cover your entire home, they do not affect your home’s signal reception. Your roof only covers about 20% to 35% of the area of ​​your home. That means the radio wave signals can still get through other areas like the walls of your home.

It’s also important to note that most modern devices come with more powerful antennas that can handle signal interference, so you don’t have to worry about poor reception.

What is a radiant roof barrier and how does it work?

A radiant roof barrier is a sheet of metal made of a highly reflective material such as foil. It is used to help homeowners save on energy bills by reducing heat gain in the home. With minimal heat getting through, you don’t have to make your cooling systems work as hard to keep the temperature in your home more comfortable, especially during the hot summer months.

Radiant roof barriers make homes cooler by reducing heat gain from radiation or that coming from the sun. The roof primarily captures the sun’s rays and the radiant energy emanating from the sun heats it. Without a radiative barrier, heat is transferred to adjacent parts of the home by conduction.

Due to its highly reflective surface, the radiant barrier reflects heat back to its external source. As a result, the heat does not get into the house. Ideally, there should be no heat gain.

For this thermal barrier to be effective, it should face an air space. The gap is where the radiant heat is transferred. When there is no air space, the aluminum conducts heat instead, making your home warmer.

It would also help if the radiation barrier were free of dust and other unwanted particles on its surface. Dirt will cover parts of its reflective surface, reducing its efficiency at reflecting heat back to its outside source.

According to experts, radiation barrier films have a reflectivity of 97%, which means that only 3% of the heat coming from the sun passes through this material. This is beneficial for those who live in warm and sunny climates. It reduces energy costs by up to 10% because you don’t have to use your cooling system as heavily.

How long does a radiant barrier last? Radiation barriers are a popular choice for home energy saving solutions due to their durability. They have an estimated life expectancy of 10 years or more. However, the number of layers a radiation barrier has does not determine its strength. It’s about the quality of the product. It also comes with a scrim layer in the middle to improve its durability against extreme temperatures. Many homeowners have confirmed using these materials and have had no problems with their foil radiation barriers even if they were installed more than a decade ago. This makes beam barriers inexpensive and worth the money. They have a long service life, you feel more comfortable in your home and you can look forward to big savings on your energy costs, especially in summer. How much does it cost to have a radiation barrier installed?

The average cost of installing radiation barriers is $1,700. It can be as low as $740 or as high as $2,840 depending on the size of the room you will be installing it in. Other important factors that would affect the overall cost are labor, type of radiation barrier, and location of insulation.

If you use double-sided film radiation barrier, expect the price to be higher than single-sided thermal barrier. The average price of a single-sided barrier is $0.10 to $0.25, while double-sided typically cost $0.90 per square foot.

The larger the area your radiation barrier must cover, the higher the cost. Also, the price goes up as the work gets more complex.

It is recommended that you hire a professional to install your radiation barrier. But you can also choose to do the job yourself if you have the skills, especially if you’re just laying it over existing insulation. This will help you save a lot on labor costs which can range from $30 to $80 an hour.

Does radiation barrier work without insulation?

Radiation barriers and insulation are two ways to protect your home from changing weather conditions. Both help keep the temperature in your home at a comfortable level with minimal cost to your HVAC system.

However, these two materials work differently. Radiant barriers reflect the heat coming from the sun, so it doesn’t stand a chance of entering your home. They block heat and prevent it from entering your home.

On the other hand, insulation materials resist and slow the flow of heat out of your home. Heat can still enter (or exit) but it travels more slowly to different parts of your home.

Because they have different functions, it’s best if you use a radiation barrier in addition to any type of insulation you have installed for your home. This ensures that the 3% of heat that is able to escape from the radiant barrier is absorbed by the insulation material and does not significantly affect the temperature in your home.

With either material you have a very strong line of defense against heat and would effectively minimize the heat input into your home. Therefore, your HVAC system does not have to work overtime to ensure the temperature is within your comfort level. This means that you will spend less on energy costs and lower your monthly electricity bills.

Final Thoughts

Don’t hesitate to install a foil radiation barrier on your roof. It’s cost-effective as you enjoy savings on your electricity bills, you have a cooler home and it doesn’t significantly affect your cell phone, WiFi and TV reception.

If you want to learn more about home insulation, you can visit the following posts:

What is the Best Attic Insulation for Texas?

Can You Paint Foil Insulation [And How To]

One of the most common questions we get is explaining why exactly an air gap is required for the radiation barrier to work.

First, you need to understand exactly what radiant heat is. Radiant heat is a form of heat that spreads across either an air gap or a vacuum.

When you walk into the kitchen and stand a few feet in front of the oven, you can feel the heat coming through the kitchen – that’s radiant heat. Now if you go upstairs and put your hand on the stove, you’ve eliminated the air gap – now you basically have a solid body between the stove and your hand. Heat flowing into your hand is conduction, or conductive heat flow. By using radiation barrier film, the film can only reflect heat traveling across an air gap. So take a hot pan and place your hand a few inches across it, now you can feel the radiant heat emanating from the pan, right?

If you take a piece of foil and pull it firmly across the top of the pan a few inches away and place your hand on the foil, you will feel almost NO heat emanating from this pan. The heat comes up, hits the foil and bounces back. This is reflectivity. Radiation barrier film has a reflectivity of 97%, basically it only transmits about 3% of that heat.

If you place the foil directly in/on the pan and hold your hand a few centimeters above it, the foil is now working on the so-called emissivity quality. This is the ability to prevent the release of heat (i.e. not give off heat) and it is basically the opposite of reflectivity. Foil has an emissivity of 0.03 or 3%. So you could hold your hand in this pan all day and your hand would never burn because the foil just doesn’t give off much heat.

If you were to take your hand and place it directly on the foil, you have now eliminated that air gap and are now back in conduction. This heat will flow extremely efficiently from the pan, through the foil and into your hand. These are exactly the same principles that apply to installing a radiation barrier in any assembly. You MUST have an air gap to get either the emission quality or the reflection quality you are looking for, otherwise the film will not function as a radiation barrier.

How much air gap is required? Doesn’t insulation count as airspace?

Usually we suggest you have an air gap between 1/2″ and 3/4″ for the radiation barrier to work. Larger air gaps also work well – they encourage ventilation of the film, helping to keep the air dry and the air temperature lower.

Insulation is technically a solid with a lot of air in it, so it is NOT an air gap. You literally have to have a VOID, nothing in the air gap but the air itself. So if you’re installing under a roof or in a wall, you need to create an air gap. It doesn’t matter which side the air gap is on, the foil works the same whether it uses reflectance or emissivity to block heat transfer.

No air gap = no radiant heat = it won’t work!

For radiant heat to exist, this air gap MUST be present. If you don’t have that air gap, you scientifically may not have radiant heat because if you put two products together and eliminate that air gap, you have conduction or conduction heat. If you don’t have radiant heat, you don’t need to install a radiant barrier – it just won’t work. Hopefully this clarifies exactly why an air gap is REQUIRED if you want to install a radiation barrier.

Here’s a pretty good article on the subject.

“Radiant barrier spray paint is essentially a liquid film. While not all Radiant barrier paints are created equal, they are basically made by grinding pure aluminum into a fine powder and then mixing it with clear coat. As soon as the clear coat paint dries the aluminum powder forms an aluminum layer.

The best radiation blocking spray available only to commercial contractors is an environmentally friendly, water-based, low-emission paint called HeatBloc-75, Radiance e.25, or Lo/MIT. If the paint is applied correctly it reflects around 75% of the radiant heat and can be a very good product.

To get good results with radiant barrier paint, a few things are required:

The rafters are fully sprayed (this will usually cost more if you can get an estimate).

The paint is applied with the correct opacity (many contractors apply it either too thin or too thick).

The color is not diluted. There are some contractors (even big ones that advertise heavily) that water cut* the paint to extend opacity. *Cutting is when water is added to the paint; it is scam to save cost.

As a result, the true effectiveness of the radiation barrier paint installed by many contractors is only around 15-40% reflectance. The typical consumer cannot tell the difference between a good installation and a bad job without testing.

Radiant Barrier Paint Spray is not a good Do It Yourself (DIY) project. The fumes are noxious, you must use a VOC respirator, a high end airless sprayer, the right size spray tip and pressure to get proper coverage and clear clogs. Forget about roller painting as this is impossible due to thousands of nails sticking through the roof. Also, using a brush to apply it manually would take forever. Most people who try it themselves will actually blow too much paint and the material cost alone will be over $0.30/ft. Since the cost of radiant barrier film is only less than $0.13/ft, it’s obvious that it’s not only a better product, it’s also a better deal.

Different brands of colors and test results

Reflective Coatings Comparison Chart Many companies have developed reflective barrier spray paint. In fact, they are not true radiant barriers as they all reflect less than 90% of the heat, which is the definition of a true radiant barrier; technically they are reflective coatings. Below is a table with some test results from RIMA (Reflective Insulation Manufacturers Association) who conducted independent tests on all different radiant barrier colors.

Note that the best paint still emits 22% of radiant heat compared to just 3% for radiant barrier film. Some colors claim to be award-winning, although the award they receive has yet to be identified or significant.

In addition, the color tests were carried out on perfectly smooth samples applied under laboratory conditions; these conditions are different than your attic. Your attic is made of porous wood that likes to soak up paint rather than hold it on the surface to create a smooth, glossy film that would be required to show its full potential. To ensure that the paint comes close to the tested emissivity, the wood surface must first be primed with a primer.

Why you should use Radiant Barrier Foil

The main reason you should consider foiling over color is that with color you basically rely on the product to deliver results, while with foil you simply need the person (whom you can be). to complete the installation. As long as the foil is placed somewhere between the roof/rafters and the insulation, it reflects 97% of the radiant heat.

This is undeniable; Radiant barrier film works!

In addition, it is actually difficult to attach the film incorrectly. This is the main difference between quality assurance and quality control. You can be sure that the reflective film works; while you can only hope that the reflective coating is installed correctly. We do not sell or install radiant barrier paint; We only sell Radiation Barrier Reflective Foil Insulation because it is the best.

The problem occurs when reflective paint is applied too thinly or when water is added to the paint/a low quality cheap paint is used. Then what? Then the clients don’t get the promised results or the cool attic.

To offset this disappointment, some companies have resorted to things like giving away free solar fans. Sure, if you put an attic fan in the attic, it will lower the attic temperature and could even bring it close to the outside temperature. However, it doesn’t matter what type of fan it is, a fan doesn’t stop radiant heat transfer. A cooler attic is nice, but what we really need to do is reduce the temperature of the insulation. For more information, see our article on air temperatures versus surface temperatures and how they affect your home.

RadiantGUARD® radiation barriers and reflective insulation products can be used in unlimited ways to control heat transfer. Listed below are just a few of the most popular construction applications.

Installation of the radiation barrier

Installation of the radiation barrier in the attic

Most of the heat entering a home comes through the roof. RadiantGUARD® Radiant Barrier Foil Insulation installed in an attic can reduce attic temperatures by up to 30 degrees when stapled to the underside of rafters by blocking up to 97% of the radiant heat striking its surface. REFLECTS and thereby reduces heat transfer from the attic to living quarters, resulting in lower utility bills. This method also reduces the heat exposed to attic-mounted AC ducts, allowing them to operate more efficiently.

A secondary installation method, rather than installing under the rafters, is to run the foil insulation above the attic. Although this type of attic installation does not lower the temperature of your attic, it still REFLECTS up to 97% of the radiant heat that hits its surface, reducing heat transfer from the attic to the living quarters, resulting in lower utility bills. To compensate for the exposed AC wiring with this installation method, you can simply place a blanket of radiant barrier over the wiring to protect it from the heat.

Note: If you choose to install above the attic, remember that condensation will form under a perforated radiant barrier due to sudden extreme temperature differences between the air below the barrier and above the barrier, typically found in colder climates during winter can form. Read more about condensation).

General installation tips

The following tips are designed to help reduce the labor time involved in installing radiant barriers and simplify your radiant barrier installation project.

Start early in the morning when your attic is coolest.

Carry all your radiation barrier and tools to the attic to avoid unnecessary trips back and forth.

Have plenty of water on hand and drink even if you don’t think you’re thirsty; especially in the summer months.

If your attic is not well lit, bring an extra light source.

Find a centrally located area to set up your workspace.

Always be careful of the roof beams you walk on. Some are prone to “rolling” if not securely attached to the attic floor.

As a DIYer, don’t try to do a big job in one day. Take your time and spread the installation over several days to take advantage of the cooler hours of the day.

For professional contractors, work in groups of two to three people. Having someone focus on cutting the product and handing it off to someone else to install it helps reduce installation times.

Installing Radiation Barrier Under Rafters ( PREFERRED INSTALLATION METHOD ) Recommended Product : RadiantGUARD ® Ultima – FOIL Radiation Barrier , Breathable ( this version is perforated to allow indoor moisture to easily permeate in and out of your home ) . Installation Summary: Starting 3 inches from the top apex (or ridge vent), install our Ultima-FOIL breathable radiant barrier across the bottom of the rafters (horizontal/perpendicular to the rafters) from one end of the roof to the other. Staple the radiator barrier to each rafter.

Note: If your roof top is too high, pick a point and create a false ceiling where the radiative barrier runs from one side of the roof to the other (this is known as the “flat top” method), then follow the remaining instructions for all sides of your roof. Work your way down to the underside of the roof, install a second row that overlaps the first row by two (2) inches, and staple to each rafter. Continue with the instructions until you reach the wall plate.

“Wall Panel” is the horizontal piece of wood that sits at the top of each outer side wall of your structure. In the attic, the wall panel is along the outer edges of the attic. All reveal openings are outside of this wall panel. If you have gable walls (outer vertical side walls of the roof) install in the same way, making sure to cut out material above any vents to allow air flow.

Click here for detailed instructions: #ad: As an Amazon Associate, we receive a commission from your qualifying purchases.

Attic Installation ** Recommended Product: RadiantGUARD® Ultima-FOIL Radiation Barrier Breathable (** Note that condensation will form under a perforated radiation barrier due to sudden extreme temperature differences between the air and above the radiation barrier typically found in colder climates can form in winter Read more about condensation).

Installation Summary: Starting at one end of your attic, install our Ultima-FOIL breathable radiation barrier over attic joists, plywood decking, or existing insulation. Use a stick (1/4 inch profile bar with a nail on the end works well) to push the barrier into tight spaces in your attic. Continue covering the attic by overlapping each section of the already unrolled radiant barrier by 2 inches. When laying foil insulation, it is not necessary to lay it down smooth or flat. It is also not necessary to tape the seams. You can staple the barrier in place if you’d like, but it’s not necessary. Tack the radiation barrier to all known walls in your attic, overlapping each piece by 2 inches. Cut out any material around equipment that generates heat and/or protrudes through the attic (canister lamps) and mark any covered electrical outlets on the radiation barrier. Click here for detailed instructions:

A good tip related to installing the radiation barrier directly in the attic is to tape an outline of all the underlying decking that you walk on to access various storage areas or equipment in your attic. By surrounding these decking boards with colorful tape, you and future contractors or tradesmen accessing your attic can easily identify where to go safely and eliminate the risk of stepping through ceiling drywall in the wrong place .

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Cathedral Ceiling Installation Suggested Products: RadiantGUARD® Ultima-FOIL Vapor Control Layer OR Single/Double Reflective Bladder Installation Summary: Install uncoated ground insulation between the rafters and ensure there is at least 1 inch ventilation clearance between the ground insulation and the underside of the roof covering is. Check Check local regulations to determine if you need to comply with an increased airspace. If necessary, you can install vents or baffles to ensure proper airflow channeling. Unroll the reflective insulation and staple it to the bottom of the rafters. Seal all seams with aluminum Apply profile strips every 16 inches perpendicular to the bottom of the Radiation Barrier

rafters. Install drywall to the top rails as usual. Click here for detailed instructions: Alternative installation only for AL, AR, CA, GA, FL, LA, MS, NC, NM, NV, OK, SC, TN and TX: In the above states, you can install the FOIL Double Bubble staples insulation directly to the roofing rather than laying it to the underside of the rafters as described above. A minimum of 1 inch air space must be left between the bladder insulation and the underlying fiberglass insulation.

With this installation, you do not need to attach any top rails before installing the drywall.

siding applications

Radiant barriers can be extremely effective at reducing radiant heat transfer when used in exterior siding applications, but again there MUST be an air space on at least one side of the radiant barrier for it to function. In this application, a radiative barrier is installed like a typical house siding, but before the siding is installed you must fit 1 x 2 strips of veneer across the top of the radiative barrier to which the siding can be attached. This creates the necessary air space for the radiation barrier to be effective. Installation behind brick or facade as a house wrap Recommended product: RadiantGUARD® Ultima-FOIL Radiation Barrier, Breathable (this version is perforated to allow moisture from your house to easily permeate in and out of your house). Installation Summary: Starting at one end of your attic, install our Ultima-FOIL breathable radiation barrier over attic joists, plywood decking, or existing insulation. Use a stick (1/4 inch profile bar with a nail on the end works well) to push the barrier into tight spaces in your attic. Continue covering the attic by overlapping each section of the already unrolled radiant barrier by 2 inches. When laying foil insulation, it is not necessary to lay it down smooth or flat. It is also not necessary to tape the seams. You can staple the barrier in place if you’d like, but it’s not necessary. Tack the radiation barrier to all known walls in your attic, overlapping each piece by 2 inches. Cut out any material around equipment that generates heat and/or protrudes through the attic (canister lamps) and mark any covered electrical outlets on the radiation barrier. Click here for detailed instructions:

Roofing Applications A radiant barrier can be very effective at BLOCKING radiant heat when installed in conjunction with roofing and siding material, however the radiant barrier MUST be installed with an air space on at least one side of it. As long as there is at least 3/4 inch air space on either side of the radiant barrier, the application will effectively BLOCK radiant heat. For more information on why a radiative barrier must have an air space on one side To be effective please read our What is a Radiative Barrier page Roofing systems that use purlins or battens/counter battens are ideal for adding a radiative barrier as the roofing easily already provides the required air space Metal, tile and slate roofing systems are examples of such roofing systems where a radiation barrier can easily be incorporated. Just as important as the airspace on a radiant barrier is the requirement that a radiant barrier remain clean and dry with each application. The image below shows a roof batten/batten system with a slate/tile material with a radiation barrier on top of the battens. The radiation barrier is installed on top of the battens in non-waterproof applications to provide a constant barrier to stay dry while maintaining the 3/4″ airspace requirement If the roofing material is waterproof it is sufficient to install the radiative barrier on the roofing felt with the batten on top We recommend our Ultima-FOIL vapor barrier (solid) as a radiative barrier for roofing applications Do not do this… As a radiative barrier requires air space on at least one side, installing directly under the felt and shingles will NOT allow the radiant barrier to block radiant heat, instead conducting heat from the shingles and felt all the way through the barrier, into the attic and eventually into the living quarters Instead, do this… Wen When installing an asphalt shingle roof, you should install the radiation barrier on the underside of the roofing or rafters in the attic below. Reflective Bubble Insulation Applications Note: Our bubble insulation products are solid vapor barriers (i.e. not vapor permeable) and therefore serious moisture, health and durability issues can result from improper installation. The R-values ​​given below will vary depending on the installation method, depending on the size of the air space surrounding the product and the direction of heat flow. Because of these variables, you can achieve several different R-values ​​with a base product. Wall Installations Most people are familiar with extreme heat in attics, but there is a secondary method of heat transfer into a building structure; through the walls. Radiation barriers installed as house envelopes on new construction projects, or bubble insulation retrofitted to wall systems, can block much of the heat entering the living space through the walls. Installation Instructions: Install in sidewalls 2″ x 4″ wall studs with R-13 unlined – Installation R-value 16.0 (horizontal heat flux) – achieved by creating a 3/4″ air space between bladder insulation and interior wall. 2″ x 6″ wall studs with R-19 Unlined – Installation R-Value 22.0 (Horizontal Heat Flow) – Achieved by creating a 3/4″ air space between bladder insulation and inner wall.

Installation in Side Walls Installing Underfloor Heating Underfloor heating systems have been around for centuries not only to keep floors warm, but also to heat the cooler air near the floor caused by cold air falling while hot air rises in a room. A radiant barrier used in conjunction with underfloor heating can help trap heat in the floor so it doesn’t escape into a basement or the floor below. Our reflective insulation is the ideal product for all underfloor heating systems and serves as a vapor barrier against moisture penetration from below. Installation instructions: Installation in concrete – R-value 1.1 (heat flow downwards)

Installation in concrete – (downward heat flux) Installation under floor joists – R-value: 17.0 (downward heat flux) – achieved by creating a 6 inch closed air space above the bladder insulation beneath the overlying flooring. Crawl space installations Reflective insulation is also an ideal solution for keeping floors warm and blocking heat loss through floors, even without the use of underfloor heating systems. When installed in a crawl space, our reflective insulation products block up to 97% of radiant heat loss through floors Floor keeping keeps floors warm and reduces cold drafts. This in turn keeps living spaces warmer, further increasing home comfort and reducing the heating bills associated with maintaining a constant room temperature. – Achieved by creating a 9 1/2 inch closed air space between the bladder insulation and the overlying flooring.

Building installations of metal

Bladder insulation not only blocks 95-97% of radiant heat hitting its surface, but also provides the necessary thermal separation to eliminate condensation problems in metal buildings. Roof Installation Instructions: New Metal Roofs (Open Interior)

With thermal break – R-value 9.2 (heat flux down) R-value 4.1 (heat flux up) – achieved by creating a closed air space of 3/4 inch between roof and bladder insulation and an 8 inch air space between insulation and finish interior (if available). Without thermal break – R-value 7.6 (heat flux down) R-value 3.9 (heat flux up) – achieved by creating a closed air space of 3/4 inch between roof and bladder insulation and an 8 inch air space between insulation and the interior fittings (if available).

(open interior) – R-value 11 (downward heat flux) R-value 4.4 (upward heat flux) – achieved by creating an 8 inch closed air space between the roofing and bladder insulation.

Retrofit Metal Roofing Installation Instructions: New metal walls (open interior) with thermal break – R-value 5.6 (horizontal heat flux) – achieved by creating a 3/4 inch closed air space between the outer siding and the bladder insulation and an 8″ air space between insulation and interior design.

(horizontal heat flow) – achieved by creating a 3/4″ closed air space between the outer liner and bladder insulation and an 8″ air space between the insulation and inner liner. With no thermal break – R-value 4.7 (horizontal heat flux) – achieved by creating a 3/4 inch closed air space between the outer panel and the bladder insulation and an 8 inch air gap between the insulation and the inner panel (if retrofit metal walls). (open interior) – R-value 4.5 (horizontal heat flow) – achieved by creating an 8 inch closed air space between the outer wall and the bladder insulation.

Post Frame/Post Barn Installations Bubble insulation can also help block radiant heat in post frame building structures and prevent dew point condensation problems. Our bladder isolation also provides no growth medium or nutritional value for fungi, insects or rodents. Instructions for roof assembly:

New post frame/pole barn roofs (open interior)

Bottom of Purlins – R-value 9 (downward heat flux) R-value 4.4 (upward heat flux) – achieved by attaching to the underside of 2″ x 4″ purlins, creating a 2″ closed air space between bladder insulation and metal exterior Roof.

(Heat Flux Down) (Heat Flux Up) – Achieved by creating a 2 inch closed air space between bladder insulation and metal outer roof. Across Purlins – R-value 6.4 (downward heat flux) R-value 4.3 (upward heat flux) – achieved by attaching to the top of 2″ x 4″ roof purlins with a minimum of 3/4″ curtain between the purlins.

Post frame / pole barn roof retrofit

Bottom of Purlins – R-value 9 (downward heat flux) R-value 4.4 (upward heat flux) – achieved by attaching to the underside of 2″ x 4″ purlins, creating a 2″ closed air space between bladder insulation and metal exterior Roof.

(Heat Flux Down) (Heat Flux Up) – Achieved by creating a 2 inch closed air space between bladder insulation and metal outer roof. Underside of truss – R-value 10 (downward heat flux) R-value 3.7 (upward heat flux) Wall installation guide: New post frame/bar barn walls (open interior)

Inside the Girts – R-value 5.3 (horizontal heat flow) – achieved by creating a 1 inch air space between the bladder insulation and the outer panel.

(horizontal heat flow) – achieved by creating a 1 inch air space between the bladder insulation and the outer panel. Outside the girts – R-value 4.7 (horizontal heat flux) – achieves the bladder insulation and outer skin by creating a minimum of 3/4 inch air space between them. Retrofit Post Frame / Post Barn Walls (Open Interior)

Inside the Girts – R-value 5.3 (horizontal heat flux) – achieved by creating a 1 inch air space between the bladder insulation and the outer panel is the ideal choice for insulating new concrete floors against heat loss. It can be used in conjunction with or without a radiant heat hose to keep the floor warm. The product is to be laid out FOIL side down towards the ground WHITE side up over which the radiant heating hose and fresh concrete are to be fitted Foil side down to avoid contact with the concrete which will result in corrosion of the Foil through which alkalis in fresh concrete could pass WHITE Double Bubble insulation used in a concrete floor application is stated to achieve an estimated R-value of 1.1. The Reflective Insulation Manufacturers Association consulted a thermal performance firm to help p explain how reflective insulation works in a concrete slab application. Below is a direct quote from this study: “To more fully understand the impact of reflective insulation materials in concrete floor systems, RIMA engaged the services of a thermal performance consulting firm (R&D Services, Inc.). Thermal efficiency calculations were used to estimate a typical case of heat loss reduction for a conventional concrete floor system. The calculation is based on steady-state thermal conditions with an isothermal plane at the heating pipes and a plane between the gravel and the ground. The floor temperature was 55 degrees Fahrenheit, while the temperature of the heater pipes was 125 degrees Fahrenheit. The calculation assumes two inches of concrete (R-0.10) under the heater pipes and five inches of gravel (R-0.75). Between the concrete and the gravel is a reflective insulation material (R-1.10) (the total thickness of the concrete floor system is approximately 22.9 cm). The system R-value of R-1.95 re reduces heat loss by 56% compared to the same concrete floor system without insulation. Concrete Floor/Slab Instructions: Concrete Floor/Slab

Masonry/Basement Wall Mounted Reflective Insulation makes an excellent basement wall insulator. It acts as a vapor barrier, resists fungus and mildew, and also controls dew point issues. R-values ​​are not affected by a wet basement environment, unlike fiberglass insulation. basement / masonry

Other Installations Reflective insulation applications are only limited by your imagination. Below are some more installation applications. Installation Instructions: – R-value 4.5 (horizontal heat flux) – achieved with 5/8″ air space between product and water heater. Water heater

The albedo of different types of roofs

Reflective surfaces can provide high solar reflectance (the ability to reflect the sun’s visible, infrared, and ultraviolet wavelengths, thereby reducing heat transfer to the surface) and high thermal emittance (the ability to radiate absorbed or unreflected solar energy). [1] Reflective surfaces are a form of geoengineering.

The most well-known type of reflective surface is a type of roof called a “cool roof”. While cool roofs are most commonly associated with white roofs, they come in a variety of colors and materials and are available for both commercial and residential buildings.[2] Today’s cool roofing pigments enable EnergyStar certification of metal roofing products in dark colors, even black.

Sun-reflective cars or cool cars reflect more sunlight than dark cars, reducing the amount of heat that is transferred to the interior of the car. Therefore, it helps reduce the need for air conditioning, fuel consumption and emissions of greenhouse gases and urban air pollutants.[3]

Cool Color parking lots are parking lots that have been coated with a reflective layer of paint.[4] Cool sidewalks designed to reflect solar radiation may use modified mixes, reflective coatings, transmissive sidewalks, and vegetated sidewalks.

Benefits of Cool Roofs[edit]

Cool roofs can provide both immediate and long-term benefits in hot climates, including:

Savings of up to 15% in annual air conditioning energy consumption for a one-story building [2] [6]

Helps mitigate the urban heat island effect. [7]

Reduced air pollution and greenhouse gas emissions, and significantly offsets the warming effect of greenhouse gas emissions.[8]

Cool roofs achieve cooling energy savings in hot summers but can increase heating energy loads in cold winters.[9] Therefore, the net energy savings of chilled roofs vary by climate. However, a 2010 energy efficiency study[10] addressing this issue for air-conditioned commercial buildings in the United States found that summer cooling savings outweighed winter heating losses, even in cold climates near the Canada border and the US usually predominate, resulting in savings in both electricity and emissions. Without a proper maintenance program to keep the material clean, the energy savings from cool roofs can decrease over time due to albedo degradation and pollution.[11]

Years of research and practical experience of roofing membrane degradation have shown that the heat of the sun is one of the strongest factors affecting durability. High temperatures and large seasonal or diurnal variations at the roof level affect the longevity of roof membranes. Reducing the extremes of temperature changes will reduce the occurrence of damage to membrane systems. Covering membranes with materials that reflect ultraviolet and infrared radiation reduces damage caused by UV and heat degradation. White surfaces reflect more than half of the radiation that hits them, while black surfaces absorb almost all. White or white coated roofing membranes or white gravel cover seems to be the best approach to control these problems when membranes must remain exposed to solar radiation.[12]

If all urban flat roofs in warm climates were whitened, the resulting 10 percent increase in global reflectivity would offset the warming effect of 24 gigatons of greenhouse gas emissions, or the equivalent of taking 300 million cars off the road for 20 years. This is because a 93 square meter white roof will offset 10 tons of carbon dioxide over its 20 year lifespan.[13] In a 2008 real world case study [14] on large-scale cooling from increased reflectivity, the province of Almeria in southern Spain was found to have cooled by a comparative 1.6 °C (2.9 °F) over a 20-year period surrounding regions, as a result of the installation of polyethylene-covered greenhouses on a vast area that was previously open desert. In the summer, farmers whitewash these roofs to cool their crops.

When sunlight falls on a white roof, much of it is reflected and travels back into space through the atmosphere. But when sunlight falls on a dark roof, most of the light is absorbed and reflected back as much longer wavelengths that are absorbed by the atmosphere. (The gases in the atmosphere that absorb these long wavelengths the most have been termed “greenhouse gases”).[15] Results of a study by Syed Ahmad Farhan et al. by Universiti Teknologi PETRONAS and Universiti Teknologi MARA in 2021[2], based on Malaysia’s hot and humid climate, suggest that the selection of white roof tiles also significantly reduces the peaks in conduction heat transfer and the temperature of the roof surface, e.g. the Values ​​of heat conduction and roof surface temperature in daily profiles. In contrast, the results also show that it does not affect nighttime profiles as heat is released into the sky throughout the night. Heat emission from the building occurs due to the lack of solar radiation, which lowers the sky temperature and allows the sky to act as a heat sink, promoting heat transfer from the building to the sky to achieve thermal equilibrium.

A 2012 study by researchers at Concordia University included variables similar to those used in the Stanford study (e.g. cloud responses) and estimated that global deployment of cool roofs and sidewalks in cities would produce a global cooling effect that offsetting up to 150 gigatons is the equivalent of carbon emissions – enough to keep every car in the world off the road for 50 years.[16][17]

Disadvantages[edit]

A 2011 study by Stanford University researchers suggested that while reflective roofs lower temperatures inside buildings and mitigate the “urban heat island effect,” they may actually increase global temperature.[18][19] The study found that it did not take into account the reduction in greenhouse gas emissions that results from the building energy savings (annual cooling energy saving minus annual heating energy penalty) associated with cool roofs (meaning more energy has to be used to heat the dwelling). space due to the reduction of heat from the sun in winter.) However, this only applies to areas with low winter temperatures – not tropical climates. Also, homes in areas that receive snow during the winter months are unlikely to receive significantly more heat from darker roofs since they will be covered in snow for most of the winter. A response paper titled “Cool Roofs and Global Cooling” by researchers from the Heat Island Group at Lawrence Berkeley National Laboratory raised additional concerns about the validity of these results, citing the authors’ acknowledged uncertainty, statistically insignificant numerical results, and insufficient granularity the analysis of local contributions to global feedbacks.[20]

Also, research conducted in 2012 at the University of California, San Diego’s Jacobs School of Engineering on the interaction between reflective sidewalks and buildings found that solar radiation reflected from light-colored sidewalks can increase unless the nearby buildings are constructed with reflective glass or others Mitigating factors equipped the temperature in nearby buildings, increasing air conditioning requirements and energy consumption.[21]

In 2014, a team of researchers led by Matei Georgescu, an assistant professor at Arizona State University’s School of Geographical Sciences and Urban Planning and a senior sustainability scientist at the Global Institute of Sustainability, examined the relative effectiveness of some of the most common adaptive technologies aimed at reducing the reduce global warming from urban expansion. Results of the study indicate that the performance of urban adaptation technologies can counteract this temperature increase, but also varies seasonally and is geographically dependent.[22]

In particular, what works in California’s Central Valley, such as cool roofs, doesn’t necessarily offer the same benefits for other regions of the country, such as Florida. Assessing impacts beyond near-surface temperatures, such as precipitation and energy demand, reveal important trade-offs that are often not considered. Cool roofs have proven to be particularly effective for certain areas in summer. In winter, however, the same urban adaptation strategies, when deployed in northern locations, further cool the environment and consequently require additional heating to maintain comfort levels. “The energy savings achieved during the summer season are almost completely lost during the winter season in some regions,” Georgescu said. In Florida, and to a lesser extent the southwestern states, there is a very different effect caused by cool roofs. “In Florida, our simulations indicate a significant reduction in precipitation,” he said. “The use of cooling roofs will result in a reduction in rainfall of 2 to 4 millimeters per day, a significant amount (nearly 50 percent) that will have impacts on water availability, reduced river flow and negative consequences for ecosystems. For Florida, cool roofs may not be the optimal way to combat the urban heat island because of these unintended consequences.” Overall, the researchers suggest that sensible planning and design decisions should be considered to address rising temperatures caused by urban sprawl and greenhouse gases to counteract. They add that “City-induced climate change depends on specific geographic factors that need to be evaluated when choosing optimal approaches, as opposed to one-size-fits-all solutions.”[23]

A series of Advanced Energy Design Guides has been developed in collaboration with ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers), AIA (The American Institute of Architects), IESNA (Illuminating Engineering Society of North America), USGBC (United States) developed Green Building Council) and US DOE (United States Department of Energy) in 2011. These guides aimed to achieve 50% energy savings towards a net zero energy building and covered the building types of small to medium office buildings and medium to large Boxes from retail buildings, large hospitals, and K-12 school buildings. In climate zones 4 and higher, it is recommended to follow the ASHRAE 90.1 standard for roof reflection, which does not currently require roofs in these zones to be reflective. In hardiness zones 4 and higher, cool roofs are not a recommended design strategy.[24]

In cooperation with the US DOE (United States Department of Energy) and the PNNL (Pacific Northwest National Laboratory), a series of Advanced Energy Retrofit Guides for “Practical Ways to Improve Energy Performance” was developed in 2011. These guides targeted improvements to existing retail and office buildings that could improve their energy efficiency. Cool roofs were not recommended for all sites. “In the hot and humid climate zone with a long cooling season, this measure should be more cost-effective than, for example, in the very cold climate zone. For buildings in warm climates, this measure is worth considering.”[25][26]

The Copper Development Association has conducted several studies since 2002 examining the elevated temperatures of cables in ducts on and over various roofing materials. The results concluded that temperatures were higher over cool roofs than over a darker roof material. This illustrates the idea where deflected solar radiation, when obstructed by roofing equipment, piping, or other materials, is exposed to the heat gain of radiation.[27]

According to the US DOE’s “Guidelines for Selecting Cool Roofs”: “Cool roofs must be considered in the context of their environment. It’s relatively easy to specify a cool roof and predict energy savings, but some forward thinking can prevent other headaches. Before you install a cool roof, ask yourself this question: where does the reflected sunlight go? A light, reflective roof could reflect light and heat into the taller windows of taller neighboring buildings. In sunny weather, this could create uncomfortable glare and unwanted heat for you or your neighbors. Excess heat caused by reflections increases air conditioning energy consumption and negates some of the energy saving benefits of the cooling roof.”[28]

According to the US DOE’s “Guidelines for Selecting Cool Roofs” on chilled roof maintenance: “As a chilled roof becomes fouled by pollution, foot traffic, windblown dirt, dammed water, and mold or algae growth, its reflectivity will decrease, resulting in higher temperatures . Roofs that are particularly dirty can perform much worse than indicated on the product labels. Debris from foot traffic can be minimized by designating designated walkways or restricting access to the roof. Steep pitched roofs have fewer problems with dirt accumulation because rainwater can wash away dirt and debris more easily. Some cool roof surfaces are “self-cleaning,” meaning they shed dirt more easily and maintain their reflectivity better. Cleaning a cool roof can restore solar reflection to near installed condition. Always check with your roof manufacturer for the proper cleaning procedure, as some methods can damage your roof. While it’s generally not cost-effective to clean a roof just for the purpose of saving energy, roof cleaning can be incorporated as a component of your roof’s routine maintenance program. It is therefore best to estimate energy savings based on weathered solar reflectance values ​​rather than clean roof values.”[28]

Properties[edit]

When sunlight hits a dark roof, about 15% of it is reflected back up into the sky, but most of the energy is absorbed by the roof system in the form of heat. Cool roofs reflect significantly more sunlight and absorb less heat than traditional dark roofs.[7]

There are two properties used to measure the effects of cool roofs:

Solar reflectance, also known as albedo, is the ability to reflect sunlight. It is expressed either as a decimal fraction or as a percentage. A value of 0 indicates that the surface absorbs all solar radiation, and a value of 1 (or 100%) represents total reflection.

Thermal emittance is the ability to emit absorbed heat. It is also expressed either as a decimal fraction between 0 and 1 or as a percentage.

Another method of assessing coolness is the Solar Reflectance Index (SRI), which combines both solar reflectance and emittance into a single value. SRI measures the roof’s ability to reject solar heat, which is defined such that a standard black (reflectance 0.05, emittance 0.90) is 0 and a standard white (reflectance 0.80, emittance 0.90) is 100.[29]

A perfect SRI is around 122, the value for a perfect mirror that does not absorb sunlight and has a very low emissivity. The only practical material approaching this level is stainless steel, with an SRI of 112. High reflectivity, low emissivity roofs maintain a temperature very close to ambient at all times, preventing heat gains in hot climates and minimizing heat losses in cold climates. High emissivity roofs have a much higher heat loss in cold climates for the same insulation values.

Roof Savings Calculator[edit]

The Roof Savings Calculator (RSC) is a tool developed by the US Department of Energy’s Oak Ridge National Laboratory that estimates cooling and heating savings for low pitch roof applications with white and black finishes.[30]

This tool was the collaboration of Oak Ridge National Laboratory and Lawrence Berkeley National Laboratory to provide industry consensus roof savings for residential and commercial buildings. It gives the annual net energy savings (cooling energy savings minus heating premiums) and therefore only applies to buildings with a heating and/or cooling system.[31]

Types of cool roofs[ edit ]

Chilled roofs fall into one of three categories: roofs made from chilled roofing materials, roofs made from materials that have been coated with a solar reflective coating, or green roofs.

Cool roofs[ edit ]

White thermoplastic membrane roofing (PVC and TPO) are inherently reflective and achieve some of the highest reflectance and emission measurements of any roofing material.[32] For example, a white thermoplastic roof can reflect 80 percent or more of the sun’s rays and emit at least 70 percent of the solar radiation that the roof absorbs. An asphalt roof only reflects between 6 and 26% of the sun’s rays.

In addition to the white thermoplastic PVC and TPO membranes used in many commercial cooling roof applications, research is also being done in the field of cool asphalt shingles. Asphalt shingles make up the majority of the North American residential roofing market, and consumer preferences for darker colors make manufacturing sun-reflective shingles particularly challenging, resulting in asphalt shingles having a solar reflectance of only 4% to 26%. If these roofs are designed to reflect an increased amount of solar radiation, the urban heat island effect can be reduced by reducing the need for summertime cooling costs. Although a more reflective roof can result in higher heating bills in the colder months, studies have shown that the increased heating bills in winter are still lower than the cooling cost savings in summer.[33] To meet consumer demand for darker colors that still reflect significant amounts of sunlight, other materials, coating processes, and pigments are being used. Because only 43% of light occurs in the visible light spectrum, reflectivity can be improved without sacrificing color by increasing the reflectivity of UV and IR light.[34] High surface roughness can also contribute to the low solar reflectance of asphalt shingles, as these shingles are composed of many small, roughly spherical grains that exhibit high surface roughness.[35] To reduce this, other granule materials are being investigated, such as e.g. B. flat rock flakes, which could reduce reflection inefficiencies due to surface roughness. Another alternative is to coat the granules using a two-coat process: the outer coating would have the desired color pigment, although it may not be very reflective, while the inner coating is a highly reflective titanium dioxide coating.

An off-white gravel cover can be considered an alternative option to obtain cool roofs and cool walkways.[36]

The highest SRI rating and the coolest roofs are stainless steel roofs, which are only a few degrees above ambient temperature in moderate wind conditions. Their SRIs range from 100 to 115. Some are also hydrophobic, allowing them to stay very clean and maintain their original SRI even in polluted environments. [A]

Coated roofs[ edit ]

An existing (or new) roof can be made reflective by applying a solar reflective coating to its surface. The reflectivity and emissivity ratings for over 500 reflective coatings can be found at the Cool Roofs Rating Council.[37]

Blue and red roofs[ edit ]

Researchers at Lawrence Berkeley National Laboratory have found that a pigment used by the ancient Egyptians called “Egyptian Blue” absorbs visible light and emits near-infrared light. It can be useful in building materials to keep roofs and walls cool.[38][39][40]

They have also developed fluorescent ruby ​​red coatings that have reflective properties similar to white roofs.

Green roofs[ edit ]

Green roofs create a thermal mass layer that helps reduce the flow of heat into a building. Solar reflectance from green roofs varies with plant type (generally 0.3–0.5).[43] Green roofs may not be as reflective as a cool roof but have other benefits such as evaporation which cools the plants and the immediate area surrounding the plants, helping to lower roof temperatures but of course increasing humidity levels. In addition, some green roofs require maintenance, e.g. B. by regular watering.

Cool climate[ edit ]

In some climates where there are more heating days than cooling days, white reflective roofs may not be effective in terms of energy efficiency or savings, as the savings in cooling energy use may be outweighed by winter heating disadvantages. According to the U.S. Energy Information Administration, 2003 Commercial Buildings Energy Consumption Survey, heating accounts for 36% of annual commercial building energy consumption, while air conditioning accounts for only 8% in the United States.[44] Energy calculators generally show a net annual saving for dark roof systems in cool climates.

A perfect roof would not absorb heat in summer and give off heat in winter. This would require a very high SRI to eliminate all radiant heat gains in summer and losses in winter. High SRI roofs act as a radiation barrier and create a thermos effect. Cooling roofs with high emissivity have a climatic disadvantage due to radiant heat losses in winter, which is not the case with reflective roofs made of bare metal, such as e.g. B. stainless steel, is not the case.

Case studies [ edit ]

In a 2001 federal study, Lawrence Berkeley National Laboratory (LBNL) measured and calculated the reduction in peak energy demand associated with the surface reflectance of a cool roof.[45] LBNL determined that a retrofit vinyl membrane resulted in an average 24°C (43°F) reduction in surface temperature compared to the original black rubber roof membrane on the surveyed Texas retail building, resulting in an 11% reduction in overall air conditioning energy consumption. , and a corresponding 14% drop in peak demand. The average daily summer temperature of the black roof surface was 75 °C (167 °F), but once retrofitted with a white reflective surface it measured 52 °C (126 °F). Excluding tax benefits or other incidental costs, annual energy expenses were reduced by $7,200 or $0.07/sqf (this figure includes both energy costs and peak usage charges).

The instruments measured the weather conditions on the roof, the temperatures inside the building and in the roof layers, as well as the air conditioning and the building’s total electricity consumption. Measurements were taken with the original black rubber roof membrane and then after replacing it with a white vinyl roof with the same insulation and HVAC systems.

Although a full year of actual data was collected, due to discrepancies in the data, one month of data was excluded along with several other days that did not meet study parameters. Only 36 continuous days prior to the upgrade were used and only 28 non-continuous operational days were used for the post-upgrade period.[45]

Another case study, conducted in 2009 and published in 2011, was by Ashley-McGraw Architects and CDH Energy Corp for Onondaga County Dept. of Corrections in Jamesville, New York, and evaluated the energy performance of a green or green roof, a dark EPDM roof, and a white reflective TPO roof. The measurement results showed that the TPO and vegetative roof systems had significantly lower roof temperatures than the conventional EPDM surface. The reduction in solar absorption reduced solar gains in summer but also increased heat losses during the heating season. Compared to the EPDM membrane, the TPO roof had 30% higher heat losses and the plant roof had 23% higher losses.[46]

Advertising programs[ edit ]

Throughout the US federal government[ edit ]

In July 2010, the United States Department of Energy announced a series of initiatives to more widely implement cooling roof technologies on DOE facilities and buildings across the country.[47] As part of the new effort, DOE will install a cooling roof whenever it is cost effective over the life of the roof during the construction of a new roof or replacement of an old one at a DOE facility.

In October 2013, the United States Department of Energy ranked Cool Roofs 53 out of 100 (0 to 100 weighted average) for a cost-effective energy strategy.[48] “Climate issues can affect the performance of chilled roofs. Cool roofs are more beneficial in warmer climates and can result in increased energy consumption for heating applications in colder climates. Cool roofs have less of an impact the more insulation is used. Department of Energy (DOE) offices to install cooling roofs when life cycle cost effectiveness is demonstrated when new roofs are built or old roofs are replaced at DOE facilities. Other federal agencies have also been encouraged to do the same.”[48]

Energy Star[ edit ]

Energy Star is a joint program of the US Environmental Protection Agency and US Department of Energy that aims to reduce greenhouse gas emissions and help businesses and consumers save money by making energy-efficient product choices.

For low-pitch roofing applications, a roofing product to qualify for the Energy Star label under its roofing product program must have an initial solar reflectance of at least 0.65 and a weathered reflectance of at least 0.50, per EPA testing methods. Warranties for reflective roofing products must correspond in all material respects to warranties offered for comparable non-reflective roofing products either by a particular company or in relation to industry standards.

Unlike other Energy Star certified products such as B. household appliances, this rating system does not consider the entire roof construction, but only the outer surface. Consumers (i.e. building owners) may believe that the Energy Star label means their roof is energy efficient; However, the test is not as rigorous as its equipment standard and does not cover the additional components of a roof (i.e. roof structure, fire barriers, insulation, adhesives, fasteners, etc.).[50] A disclaimer is posted on their website: “Although there are inherent benefits to using reflective roofs, consumers should research expected calculated results based on expected energy savings before choosing a roofing product, which is available on the Department of Energy’s Roof Savings Calculator.” can be found” website at www.roofcalc.com. Please remember that the energy savings that can be achieved with reflective roofs depend greatly on the construction of the facility, the insulation used, the climatic conditions, the location of the building and the depend on the efficiency of the building envelope.”[50]

Zertifizierungsanforderungen für verschiedene Kühldachprogramme Neigung min. Sonnenreflexion min. Abstrahlung min. Sonnenreflexionsindex ENERGY STAR Niedrig, anfänglich 0,65 Niedrig, gealtert 0,50 Steil, anfänglich 0,25 Steil, gealtert 0,15 Green Globes Niedrige Neigung 78 Steile Neigung 29 USGBC LEED Niedrige Neigung 78 Steile Neigung 29

Cool Roof Rating Council [Bearbeiten]

Cool Roof Rating Council [51] (CRRC) hat ein Bewertungssystem zur Messung und Berichterstattung der Sonnenreflexion und der thermischen Emittanz von Dachprodukten entwickelt. Dieses System wurde in ein Online-Verzeichnis mit mehr als 850 Bedachungsprodukten aufgenommen und steht Energiedienstleistern, Bauordnungsbehörden, Architekten und Planern, Grundstückseigentümern und Gemeindeplanern zur Verfügung. CRRC führt jedes Jahr Stichprobentests durch, um die Glaubwürdigkeit seines Bewertungsverzeichnisses sicherzustellen.

Das Bewertungsprogramm von CRRC ermöglicht es Herstellern und Verkäufern, ihre Bedachungsprodukte gemäß den spezifischen, von CRRC gemessenen Eigenschaften angemessen zu kennzeichnen. Das Programm legt jedoch keine Mindestanforderungen an die Sonnenreflexion oder die Wärmeemission fest.

Grüne Kugeln [ bearbeiten ]

Das Green-Globe-System wird in Kanada und den Vereinigten Staaten verwendet. In den USA gehört Green Globes der Green Building Initiative (GBI) und wird von ihr betrieben. In Kanada ist die Version für bestehende Gebäude Eigentum von BOMA Canada und wird unter dem Markennamen „Go Green“ (Visez vert) betrieben.

Green Globe verwendet Leistungs-Benchmark-Kriterien, um den wahrscheinlichen Energieverbrauch eines Gebäudes zu bewerten, und vergleicht das Gebäudedesign mit Daten, die vom Target Finder der EPA generiert wurden und die tatsächliche Gebäudeleistung widerspiegeln. Gebäude können eine Bewertung zwischen einem und vier Globen erhalten. Dies ist ein Online-System; Die Informationen zu einem Gebäude werden von einem von Green Globes zugelassenen und geschulten lizenzierten Ingenieur oder Architekten überprüft. Um sich für eine Bewertung zu qualifizieren, müssen Dachmaterialien einen Sonnenreflexionsgrad von mindestens 0,65 und einen Wärmeemissionsgrad von mindestens 0,90 aufweisen. Bis zu 10 Punkte können für eine Dachbedeckung von 1–100 Prozent entweder mit Vegetation oder stark reflektierenden Materialien oder beidem vergeben werden. Die physikalische Grundlage einer hohen Emittanz ist ziemlich fragwürdig, da sie lediglich ein Material beschreibt, das leicht Wärme im Infrarotbereich an die Umgebung abstrahlt und so zum Treibhauseffekt beiträgt. Hochreflektierende Materialien mit niedrigem Emissionsgrad reduzieren den Energieverbrauch viel besser.

LEED [ bearbeiten ]

Das LEED-Bewertungssystem (Leadership in Energy and Environmental Design) des U.S. Green Building Council ist ein freiwilliger, sich ständig weiterentwickelnder nationaler Standard für die Entwicklung nachhaltiger Hochleistungsgebäude .[Zitat erforderlich]

Im Gegensatz zu einer Bauordnung wie der Internationalen Bauordnung dürfen nur Mitglieder des USGBC und bestimmte „hausinterne“ Ausschüsse den Standard auf der Grundlage eines internen Überprüfungsprozesses hinzufügen, entfernen oder bearbeiten. Über Musterbauordnungen wird von Mitgliedern und „hausinternen“ Ausschüssen abgestimmt, aber es sind Kommentare und Aussagen der Öffentlichkeit während jedes einzelnen Entwicklungszyklus der Normen bei Anhörungen zur öffentlichen Überprüfung möglich, die im Allgemeinen mehrmals im Jahr stattfinden.[52]

Gemäß der LEED-Version 2009 müssen mindestens 75 % der Dachoberfläche Materialien mit einem Sonnenreflexionsindex (SRI) von mindestens 78 verwenden, um den Sustainable Sites Credit 7.2 Heat Island Effect-Roof zu erhalten. Dieses Kriterium kann ebenfalls erfüllt werden durch Installation eines begrünten Daches für mindestens 50 % der Dachfläche oder Installation einer Kombination aus hoher Albedo und begrüntem Dach, die dieser Formel entspricht: (Dachfläche mit Mindest-SRI-Dach/0,75) + (Begrünungsdachfläche/0,5) ≥ Gesamtdachfläche.[53]

Beispiele für LEED-zertifizierte Gebäude mit weißen reflektierenden Dächern sind unten aufgeführt.[54]

Name des Gebäudes Eigentümer Standort LEED-Stufe Wildomar Service Center Südkalifornien Edison Wildomar, Kalifornien Platin[55][56] Donald Bren School of Environmental Science & Management University of California, Santa Barbara Santa Barbara, Kalifornien Platin Frito-Lay Jim Rich Service Center Frito- Lay, Inc. Rochester, New York Gold Edifice Multifunction Travaux Public et Services Gouvernementaux Canada Montreal, Quebec Gold Seattle Central Library City of Seattle Seattle, Washington Silver Hauptsitz der National Geographic Society National Geographic Society Washington, D.C. Silver Utah Olympic Oval Salt Lake City Organisationskomitee der Olympischen Winterspiele 2002 Salt Lake City, Utah Zertifiziert Premier Automotive Group North American Headquarters Ford Motor Company Irvine, Kalifornien Zertifiziert

Cool Roofs Europa und andere Länder [ bearbeiten ]

Dieses Projekt wird von der Europäischen Union im Rahmen des Intelligent Energy Europe Programms kofinanziert.

The aim of the proposed action is to create and implement an Action Plan for the cool roofs in EU. The specific objectives are: to support policy development by transferring experience and improving understanding of the actual and potential contributions by cool roofs to heating and cooling consumption in the EU; to remove and simplify the procedures for cool roofs integration in construction and building’s stock; to change the behaviour of decision-makers and stakeholders so to improve acceptability of the cool roofs; to disseminate and promote the development of innovative legislation, codes, permits and standards, including application procedures, construction and planning permits concerning cool roofs.[57] The work will be developed in four axes, technical, market, policy and end-users.

In tropical Australia, zinc-galvanized (silvery) sheeting (usually corrugated) do not reflect heat as well as the truly “cool” color of white, especially as metallic surfaces fail to emit infrared back to the sky.[58] European fashion trends are now using darker-colored aluminium roofing, to pursue consumer fashions.

NYC °CoolRoofs [ edit ]

NYC °CoolRoofs is a New York City initiative to coat rooftops white with volunteers.[59] The program began in 2009 as part of PlaNYC,[60] and has coated over 5 million square feet of NYC rooftops white.[61] On Wednesday, September 25, 2013 Mayor Michael R Bloomberg declared it “NYC °CoolRoofs Day” in New York City with the coating of its 500th building and reducing the carbon footprint by over 2000 tons. Volunteers use paintbrushes and rollers to apply an acrylic, elastomeric coating to the roof membrane.[62] A 2011 Columbia University study of roofs coated through the program found that white roofs showed an average temperature reduction of 43 degrees Fahrenheit when compared to black roofs.[63]

White Roof Project [ edit ]

White Roof Project is a US nationwide initiative[64] that educates and empowers individuals[65] to coat rooftops white. The program’s outreach[66] has helped complete white roof projects in more than 20 US states and five countries, engaged thousands in volunteer projects, and sponsored the coating of hundreds of nonprofit and low-income rooftops.

Urban heat island effect [ edit ]

An urban heat island occurs where the combination of heat-absorbing infrastructure such as dark asphalt parking lots and road pavement and expanses of black rooftops, coupled with sparse vegetation, raises air temperature by 1 to 3 °C (1.8 to 5.4 °F) higher than the temperature in the surrounding countryside.[67][68]

Green building programs advocate the use of cool roofing to mitigate the urban heat island effect and the resulting poorer air quality (in the form of smog) the effect causes. By reflecting sunlight, light-colored roofs minimize the temperature rise and reduce cooling energy use and smog formation. A study by LBNL showed that, if strategies to mitigate this effect, including cool roofs, were widely adopted, the Greater Toronto metropolitan area could save more than $11 million annually on energy costs.[69]

See also[edit]

Emergency management agencies strongly recommend the use of aluminum foil-covered cardboard inserted between windows and curtains.

Sample video title is inserted here for this video

Editor’s Note: The video version of this story is dated July 2021.

Historic heat waves shook parts of the United States in June 2021, resulting in record-breaking temperatures topping 110 degrees Fahrenheit in cities like Portland, Oregon. A heat wave the following June brought various heat warnings to almost a third of the US population.

People took to social media to share how people in homes with little or no air conditioning can beat the heat and stay cool. One method in particular stood out because users claimed it was both cheap and effective: covering windows with aluminum foil to reflect sunlight and heat out.

A TikTok video sharing the method received more than 100,000 likes and multiple tweets sharing the tactic received thousands of likes and retweets. All posts urge people to black out windows with aluminum foil.

PSA: If you are in the Pacific Northwest and have either no air conditioning or insufficient air conditioning, cover your windows with aluminum foil, shiny side out. cardboard on the inside if you can. pic.twitter.com/Fvv3yiqD50 – Kat Cosgrove (@Dixie3Flatline) June 27, 2021

THE QUESTION

Does installing aluminum foil over windows help keep the home cool?

THE SOURCES

THE ANSWER

Yes. Civil protection agencies specifically recommend the use of “aluminum foil-covered cardboard” between windows and curtains to reflect heat outward.

WHAT WE FOUND

The Federal Emergency Management Agency (FEMA) published a June 29 blog post that listed the aluminum foil tactic among six ways to combat extreme heat.

“You can keep your home cooler by insulating it and covering your windows with curtains or blinds,” FEMA said in the post. “Use window reflectors, like cardboard covered in aluminum foil, to reflect heat outward.”

Local emergency management authorities agree. The Georgia Emergency Management recommends installing “temporary window reflectors,” such as cardboard covered with aluminum foil, between windows and curtains before extreme heat arrives. Washington Emergency Management tweeted on June 22 that residents could prepare for the upcoming heatwave by putting aluminum foil-covered cardboard on their windows. Both say this reflects heat outward.

dr Mahabir Bhandari, a member of Oak Ridge National Laboratory’s Building Envelope & Urban Systems Research Group, agreed that aluminum foil and cardboard are useful for cooling the home in emergency situations. But if it’s an option, he believed it would be more effective to cover the windows from the outside rather than the inside.

“Now [when the aluminum covers the window from the outside, the sunlight] doesn’t hit the window directly, it hits this aluminum foil,” Bhandari said. “It will absorb some and some will come in, but then most of it will be reflected.”

dr Bhandari said the aluminum foil could transfer some heat through the window as the aluminum itself gets hotter, and through a process called conduction, the glass could then be heated. But that’s where the box from the FEMA recommendation comes in.

The cardboard serves as insulation and absorbs the heat from the aluminum foil. That means the window doesn’t end up getting as hot, and therefore the space behind the window doesn’t get as hot either, Dr. Bhandari.

Heat travels by a combination of radiation, conduction, and convection. According to a Department of Energy page about a cooling solution called this radiation barrier, radiation travels in a straight line from the heat source to a surface that absorbs the heat. Conduction, explains the University Corporation for Atmospheric Research, is when heat is transferred directly between two things that are in contact.

“Basically, when the sun hits your window, some heat can be reflected out and some heat can be absorbed,” said Dr. Bhandari. “And then some heat can go straight in, we call that direct radiation, and then also because your window is hot, it can also emit heat later on too.”

“So when the heat comes in, it gets locked in,” he continued. “It can’t go out the window the way it came in.”

Because of this, explained Dr. Bhandari, many windows are already built with a certain degree of reflection. Heat will not pass through a reflective surface, most of it will just bounce off. And if something prevents the window surface from getting hot, like a shutter or a piece of cardboard, then the window can’t emit heat into the room air.

If aluminum foil is not available, Dr. Bhandari that the next best strategy is to find anything at all to cover windows and keep sunlight and the heat that comes with it from getting inside. Cardboard works well here too.

According to Dr. Bhandari energy efficient windows that reflect more sunlight, window films that can be attached to windows, and shutters that can be opened and closed as needed to prevent sunlight from reaching the window in the first place.

TO VERIFY

Summer is in full swing and many homeowners are struggling to deal with the heat. Keeping the air conditioner on all the time can be expensive and annoying. A better solution is a radiant barrier for your home.

We’ll go through the benefits of these barriers, but first let’s talk a little bit about how heat works.

THE TYPES OF HEAT TRANSFER

Whether you’re trying to keep the house cool or warm, there are three heat transfer methods to think about:

Radiation. When a fire is lit, it sends out waves of heat in all directions. So does the sun. These waves hit the roofs of houses and heat them up. Management. The roof gets hotter and starts transferring heat to the other side. Heat travels through the various materials in your roof and ceiling. Finally it reaches the inside. Convection. That’s when the air around a hot object absorbs some of its heat. When the air in your home comes in contact with the ceiling, it gets warmer. This increases the temperature throughout the house.

In summer, the main mode of transmission is radiation. To keep your house cooler, you need to prevent heat waves from warming the house.

THE SOLUTION: A RADIANT BARRIER FOR YOUR HOME

Roofs are the largest source of heat in summer. It’s a prime target for the sun’s waves, so it absorbs the most heat.

Radiation barriers reflect these waves back to the source instead of absorbing them. You stay cool. That way they don’t transfer the heat further into the house. The reduction in radiation means that the other methods of transmission are also reduced.

Here are some of the benefits of a radiant barrier for your home:

1. YOU SAVE MONEY

A well-insulated home means you spend less money on maintaining a comfortable temperature.

With a barrier inside, less outside heat gets into the house in summer. However, when it is cold outside, the barrier also prevents heat from escaping the house.

Also, because you use less of the heating and cooling system, they are put under less strain. With a shorter useful life, they need to be replaced or repaired less often.

Buying a radiation barrier for your home is a smart investment. In a relatively short time, the money you save on bills will offset the price of the barrier.

2. THE BARRIER IS VERSATILE AND EASY TO INSTALL

A homeowner with little knowledge or equipment can install the barrier without assistance. All you need is enough attic space to set it up.

In addition, the barrier can be installed both during the construction of the house and after it. You can also use it to insulate other structures like garages or boathouses.

You have full control over when and where the radiation barrier is deployed.

3. BEAM BAR HAS A LONG LIFESPAN

Since it is installed in the attic, you don’t have to worry about the weather degrading it. In contrast to conventional insulators, moisture cannot harm it.

SHOULD YOU GET A RADIANT BARRIER?

The barrier significantly alleviates the summer heat and helps your home maintain a comfortable temperature. In addition, it will do an equally good job in winter.

If you’re unsure about getting the barrier, grab a free product sample pack first. It contains data sheets as well as various samples of the materials we provide.