Attic Insulation

When the sun heats a roof, it's primarily the sun's radiant energy that makes the roof hot. A large portion of this heat travels by conduction through the roofing materials to the attic side of the roof. The hot roof material then radiates its gained heat energy onto the cooler attic surfaces, including the air ducts and the attic floor. Radiant barrier / radiant foil barrier insulation reduces the radiant heat transfer from the underside of the roof to the other surfaces in the attic.

A radiant barrier's performance is determined by three factors:

1. Emissivity (or emittance) – the ratio of the radiant energy (heat) leaving (being emitted by) a surface to that of a black body at the same temperature and with the same area. It's expressed as a number a between 0 and 1. The higher the number, the greater the emitted radiation.
2. Reflectivity (or reflectance) – a measure of how much radiant heat is reflected by a material. It's also expressed as a number between 0 and 1 (sometimes it is given as a percentage between 0 and 100%). The higher the number, the greater the reflectivity.
3. The angle the incident radiation strikes the surface—a right angle (perpendicular) usually works best.

Five key benefits of installing a radiant barrier

1. Reduced heating and cooling costs (lower utility bills) 
2. Increased comfort levels
3. Increases building's energy efficiency 
4. Keeps heat out during the summer
5. Keeps heat in during the winter

We’ll, to be vague, often. Replacing your furnace filter really depends on your home’s environment. Do you have pets? Do you keep your windows open? Many more questions can be asked. But in short, check your furnace filter monthly to see if it’s collecting dust and particles. I typically change my furnace filter out when the filter starts turning gray. And that’s typically prior to the three-month filter replacement period many homeowners try to abide by.

Replacing your furnace filters often will not only save you money but will also protect your health by maintaining good air quality in your home. A furnace filters job is to help circulate clean air and to capture irritants like pollen. If your filter is too dirty the air struggles to pass through it and will make your furnace work harder. It’s important to change your filter often to prevent damage, costly repairs and to maintain your furnace so that it’s not overworked. Changing your furnace filter regularly can help reduce your heating bills.

And if high heating bills are an issue, consider installing a radiant barrier product in your attic. During the cold season when your furnace is forcing hot air through the home, radiant barrier insulation will help keep the heat from escaping through the roof. Adding radiant foil barrier will help reduce the load on your furnace.

2009 case study findings at the Energy Center at Appalachian State University showed a 20 percent reduction in an air conditioner unit's run time during seven hours of peak attic temperature. This study also indicated that the installation of a radiant barrier in an attic can make it easier for your air conditioner to do its job in the summer heat. That translates to lower electricity usage, which also impacts the carbon footprint of homes and will help reduce your utility bill.  See the complete study.

Some radiant barriers, like Enerflex, are easy to install, in both new construction or during renovation of older homes. Radiant barrier foil is used in addition to insulation, as the reflective nature of a reflective foil barrier will help reduce the movement of radiant energy—which accounts for most of the heat gain in buildings.

Key findings of the radiant barrier study include:

• A 23-degree drop in the peak attic temperature occurred in a home outfitted with radiant heat barrier versus a similar home without the barrier;
•  A 20 percent reduction in the run-time of the air conditioning unit during the seven hours of peak attic temperatures; and
• The radiant barrier improved the efficiency of cooled air delivered through the air ducts by 57 percent during this period.

Enerflex Radiant Barrier qualifies for the American Recovery Tax Credit for insulation—equating to savings of 30 percent, up to $1,500. Enerflex is also ENERGY STAR® approved and allows specifiers to earn up to five LEED points under EA 1 and MR 5. Installing Enerflex in certain applications may qualify for state and local government tax credits.

There is some controversy as to whether radiant barrier insulation reduces the life of asphalt shingles. Studies by both the University of Florida and Texas A & M University show no significant heat increase in shingles on roofs employing radiant barrier insulation in conjunction with full venting. 

Texas A&M University actually built two homes to test the effectiveness of radiant foil barrier insulation. One home without radiant barrier and one with radiant barrier. The tests concluded that there was a significant reduction in heat gain in the test home with radiant barrier insulation. There was no evidence of damage to shingles because of reflected heat.

Here are the results of the Texas A&M University Radiant Barrier Study (PDF). This study should alleviate fears about using radiant barrier foil on a home that has asphalt shingles. As long as you use full venting—that is a full ridge vent and vents along the soffit—it is OK.

Further studies at Texas Tech University have shown the cooling effect in a hot attic of radiant barrier insulation to be approximately 15 degrees with an asphalt shingle roof and 13 degrees Fahrenheit with a metal roof. How this translates into a certain percentage of cost reduction depends on the amount of insulation between the dwelling and the attic.

There are new underlayment products that go directly under a metal roof but for existing homes your choice will be limited to stapling the proper width of radiant barrier between your rafters up against the ceiling.

Radiant barrier insulation is among our list of green building products. It appears that it does live up to most of the manufacturer's claims. Here's an in-depth explanation of how radiant barrier insulation works by the U.S. Department Of Energy: DOE Radiant Barrier Information.

Professional Remodeler Magazine, a leading business to business remodeling trade publication, has selected Enerflex Radiant Barrier, by Universal Forest products, as one of the best new products for 2010. The 101 Best New Products is an editor's choice award; Enerflex radiant barrier was listed first under the Structural, Insulation and House-wrap category. The 101 Best New Products article is featured in the November 2010 issue of Professional Remodeler magazine.

About Enerflex Radiant Barrier Insulation
ENERGY STAR approved Enerflex radiant foil barrier insulation is a highly reflective, double-sided, multilayer material that blocks up to 96 percent of the sun's radiant heat. It installs between rafters to the underside of a roof and on vertical surfaces (gable ends) in an attic to reduce solar heat gain into the home. Enerflex is available in 16 and 24 inches on center in precut panels and does not require tools to install. Enerflex is available in rolls and panels and is backed by a 15-year limited warranty. Enerflex also qualifies for the 2010 Energy Tax Credit for a 30% savings or up to $1,500.

For more information and videos, visit the Enerflex newsroom.

Simply put… YES, radiant barriers work. Now don’t worry, I’m not just going to stop there, you will get a detailed explanation.

The reason a radiant barrier works at reducing energy costs is because they lessen the strain on a structure's heating and cooling system. Regardless of whether or not you are heating a structure, or cooling it, radiant foil barrier will stop the transmission of radiant heat (95-97% of it anyway).

Radiant heat is the most efficient form of heat transfer there is. It’s more efficient than convection and conduction put together. The best radiant barrier foil, stops at least 95-97% of radiant heat transmission.

What this means is that in the summer, when the sun is beating down on your roof and radiant heat is raising the temperature in your attic and interior spaces, a properly installed radiant barrier will drastically reduce that radiant heat gain. Vice versa, in the winter, when you are trying hard to keep your home warm, while the heat is rising and leaving your home through the ceiling, properly installed reflective radiant barrier insulation will reduce that heat loss by reflecting radiant heat back into the home.

Some individuals say that reflective radiant barriers are not effective and point to a specific government website (www.ornl.gov/sci/roofs+walls/radiant/rb_tables.htm) as their proof. However, after thoroughly analyzing that data, it only shows that radiant barriers are not effective in certain circumstances: when massive amounts of insulation (R38) are used and where there is no heating or cooling duct-work located in the attic. I will agree, that if you don't have any heating or cooling duct-work in the attic and your ceiling / attic space is very well insulated, then a radiant barrier will do very little towards reducing your energy bills.

Being from the construction industry however, I must say that many homes, especially in the southern regions, do have duct-work and air handlers located in their attic spaces, so even if they have the proper amount of insulation, a radiant barrier would still be quite beneficial.

Despite the fact that radiant barrier insulation has been around for more than a quarter of a century, and it has been proven effective by hundreds of research trials and on-site testing, there are still misconceptions about how radiant barriers work. Consumers have even questioned whether or not reflecting the heat out through the roof can negatively affect the roof shingles.

First of all, radiant barriers are part of a “system,” a cooling/heating strategy. The basic product is a type of aluminum foil or metalized film – much enhanced from your typical kitchen foil. This material is stapled to the underside of the top chord of the roof trusses or to the underside of the roof decking so that there will be an airspace below it to the attic floor. The radiant barrier blocks the radiant heat transfer between a surface that is giving off heat, such as a hot roof, and a surface that can absorb this heat, like conventional attic insulation.

Without a radiant barrier to block the heat coming into the attic through the roof, the heat gets radiated to the insulation which transfers it to the material it touches, primarily your home’s ceiling. Now you've got a hotter house, making you uncomfortable and causing the air conditioner to run longer to get rid of the heat.

Research has found that a radiant barrier system can block up to 97% of the heat that gets radiated downward by the roof before it gets to the insulation.

Even if your attic is well-ventilated, temperatures in a typical attic on a hot summer day can easily reach or exceed 150 degrees F. That’s why you need to get this heat out of the attic before it gets into your living space. Watch a video on simulated attic heat test with and without radiant barrier.

As for its effects on roofing material, it is pretty unlikely that radiant barrier systems can cause any damage to roof shingles even on the hottest days. Roofing materials are obviously made to withstand very high temperatures, and research has found that a radiant barrier only increases their peak temperatures by five degrees or less – not very significant when you consider that peak temperatures on the shingles can easily reach 160 to 190 degrees without causing any damage.

“Too good to be true” may be a misguided perception among many consumers. But every home is different, and insulation and airflow play a significant role in how effective a radiant foil barrier performs. Proper installation of a radiant barrier is also critical to its effectiveness.

As long as your attic is maintained with the right amount of insulation for the area and proper airflow, radiant barriers work. An Energy Star certified radiant barrier will reflect the sun’s radiant heat to help lower attic temperatures in hot climates by up to 30 degrees, allowing you to reduce the amount of energy used to cool your home. Imagine living in a home without a radiant barrier—watch this simulated attic heat test video. Now imagine yourself relaxing in a home with a radiant barrier that helps maintain a constant, comfortable temperature.

Stay cool. Start believing. I do.

Both DIYer and professional installers will find installation of Enerflex Radiant Barrier products to be simple and easy—no special tools required.

As people learn how radiant barrier insulation blocks the sun’s heat to create a more comfortable and energy-efficient home, use of radiant barrier products will become more popular. With radiant barriers becoming more common in environmentally-friendly construction, additional advancements and variations will become available. Most radiant barrier products are nominally sound but they don’t match the ease of installation found with Enerflex Radiant Barrier.

No special tools required.
Unlike most radiant barrier foil, Enerflex doesn’t require prep work at all. Enerflex's metallic foil panels allow you to simply flex the panel into place between your roof joists and release. Once complete, you're ready to start saving on energy costs and high utility bills.

Watch the Enerflex Radiant Barrier installation video
See just how easy it is to install Enerflex radiant barrier panels and start lowering your attic temperatures and your cooling costs.

Enerflex makes radiant barrier installation easy for both DIYer and professional installers. 

Radiant barrier insulation is becoming increasingly popular as people learn how it will block the sun’s heat and create a more comfortable home. And as radiant barriers become more popular for environmentally friendly construction, more varieties become available. Although many radiant barrier products are nominally sound, they don’t come close to matching the installation ease of Enerflex Radiant Barrier. Unlike most radiant barrier foil, Enerflex doesn’t require prep work at all. Simply flex the metallic film panel into place between your roof joists and release it—and it’s ready to start saving you on energy cost and outrageous utility bills.

Want to see how easy it is to lower your attic temperatures and your cooling costs?
Watch the Enerflex Radiant Barrier installation video.

Installing radiant barrier foil in your attic reduces energy use.
Traditional insulation doesn’t prevent radiant heat transfer. After traditional insulation absorbs as much heat as able, excess heat fills the space around it and makes its way down into the living areas. This increases energy use—and utility bills. Enerflex Radiant Barrier foil (metallic film) is easy to install. And it’s able to block as much as 96 percent of the sun’s radiant heat that your roof surface absorbs, for cool results including ample energy savings and a 30-degree drop in attic temperature. This brief video clip shows how installing Enerflex Radiant Barrier foil in your attic will reduce your utility bills.

But Enerflex doesn’t only keep things cool. Heat rises … and when it’s cold outside, the radiant barrier foil installed in your attic prevents heat from escaping and helps lower your heating costs. You’ll also find the indoor temperature consistently more comfortable. Find out how Enerflex works.

Another good reason to install a radiant barrier in your home? Reduced wear and tear on your air conditioner and furnace.
 

Give your air conditioning unit and furnace a break: Install radiant barrier foil in your attic. Enerflex Radiant Barrier attic foil will help you reduce repair expenses, lower replacement costs and even give your heating and cooling units a longer service life.

As more attention is paid to reducing home energy and increasing green building, radiant barrier insulation is spending time in the limelight, especially in hot climates throughout the U.S. like Texas, California, Georgia, North Carolina, Florida and Arizona. But what in the heck is a radiant barrier — and why should radiant barrier installation be at the top of your home improvement project list?

Enerflex radiant barrier and other radiant barrier insulation are made from metalized film or foil materials that reflect the sun’s radiant heat when installed in an attic space. Do radiant barriers conserve energy? Sure — that’s their job! Just be sure you understand what your radiant barrier’s savings claims mean. For example, if a product claims to reflect 90 percent of your structure’s radiant heat, that doesn't mean your utility bills will be reduced by 90 percent. 

How do radiant barriers work?
Here’s some background. Heat transfer is by conduction, by convection or radiant. Conduction transfers heat from one molecule to the next. (Think about how quickly that cold pop can warmed up as you held it. Insulation might’ve kept things cooler.) Convection involves air that moving—heat that could be reduced by a fan, perhaps. Radiant heat is harder to explain, so we’ll simplify it: You feel radiant heat in the air around you, on a toasty car seat, or beating down through the roof of your house. When roofing materials absorb the sun’s heat, that heat transfers to your attics—and that’s why your attic air gets so hot. Because that heat has no way out, it’s absorbed by insulation and ceiling drywall before making its way into the living spaces below. And now those rooms below are warmer, too. Watch a video to see how Enerflex Radiant Barrier works.

To reflect that heat and prevent it from heating up your home in warm weather, use a reflective radiant barrier. More than 90 percent of the radiant heat striking a shiny aluminum foil surface is reflected away. Your climate, your attic insulation, any shade trees and your attics ventilation (to an extent) all have an effect on your cooling costs. Some studies show that homes with duct work or HVAC equipment in the attic will realize the greatest energy saving benefits from radiant barrier insulation: If leaky ducts are drawing in steamy attic air, your HVAC system is working harder to cool that air—and it’s not working hard enough to cool your warmer living spaces.   

Enerflex Radiant Barrier could lower your attic’s temperature by up to 35 degrees. A cooler attic means lower cooling costs (and heating costs). It also means that the rooms below will be consistently more comfortable...

Watch this video to find out how easy Enerflex Radiant Barrier is installed.

With increased attention being paid to home energy reduction, radiant barriers have lately been in the green building spotlight. So, what exactly is a radiant barrier and what can a home owner expect from one?

Radiant barriers, like Enerflex, are materials that reflect the radiant heat of the sun. They are installed in roofs and walls of a structure. Do they save energy? Yes. But be careful to understand any savings claims that may be made. For example, a claim that a product reflects 90% of radiant heat does not mean it will reduce cooling bills by 90%.

So how do they decrease heat? First let’s understand the three ways heat is transferred: With conduction, heat is transferred from one molecule to the next. Holding a beer bottle warms the beer. This is bad. Insulation mitigates this. Convection involves moving air, and a fan is an example of how to reduce this type of heat. Radiant heat is a bit harder to understand. Terms like “electromagnetic waves” and “high-energy particle transmission” are thrown about in its explanation but for purposes of this post let’s just say radiant heat is noticed by you when it hits the air around you, your car seats or your home’s roof. Heat from the sun is absorbed by roofing materials and reradiates to the air in your attic. That’s why attics get so hot. This heat energy then gets absorbed by the attic insulation and ceiling drywall, then is reradiated into the living space, making the room warmer.

A radiant barrier reflects that radiant heat. Shiny aluminum foil facing a heat source reflects over 90% of the radiant heat that strikes it. How much can it save you in cooling costs? Depends on your climate, shading from trees, how much insulation you already have in your attic, and to some extent, how well the attic is ventilated. Some studies indicate the most energy saving benefits are in homes that have duct work or HVAC equipment located in the attic. Leaky ducts draw in the hot attic air causing your system to work harder to cool 140 degree air rather than the air in other living spaces.

Radiant barriers like Enerflex can cool attic temperatures 20 to 35 degrees. The radiant barrier creates a cooler attic which helps reduce cooling costs. Obviously there are comfort improvements to be noticed in the rooms just below the attic.

To see just how easy Enerflex radiant barrier installs, watch our step-by-step how-to video.

Source: Green Builder Magazine