Top Questions / Myths

Top Questions

*Click on any question to see the answer

1. What is the difference between radiant barrier, reflective insulation, and "radiant barrier paints?"

A radiant barrier and reflective insulation product are very similar in that they both reflect an average of 95-96% of the radiant heat that strikes their surfaces across and air space.  A radiant barrier is a fairly thin product that is about the thickness of a standard business card.  A quality radiant barrier has a reinforcement layer in the middle (typically referred to as a woven scrim) to make the product strong and tear resistant. 

A reflective insulation product is a thicker product with an "insulating" middle layer such as fiberglass, foam, or air bubbles. Because of the presence of the small insulating layer, a reflective insulation product by itself achieves a small R-Value typically around 1.0.  While this R-Value is for the product only, when installed in certain applications with a dead air space (sealed cavity with no air movement) a much higher R-Value can be achieved. It's the dead air space that provides the additional R-Value and the greater the dead air space, the greater the overall R-Value.  To view our measured R-Values for various applications, please see our installation instructions.

"Radiant barrier paints" are really not true radiant barriers as they fall short of the required reflectivity of a radiant barrier which is 90% or more.  They are actually termed as Interior Radiation Control Coatings (IRCC).  There are many manufacturers of such products with a wide range of reflectivity from as low as 15% to 80.5%.

As a general rule of thumb for selecting the correct product:

  • If you are looking to reflect or block radiant heat, use a radiant barrier.

  • If you also need to achieve an R-Value (typically in order to meet specific building code regulations), OR need to control condensation such as in a metal or steel building, use a reflective insulation product.

For more information on each of these products, see the information below found on our website:

2. I found many companies selling similar products so why should I buy from RadiantGUARD?

RadiantGUARD is an established company that carries an A+ Better Business Bureau rating and is a manufacturing member of the American Standards Testing Methods.  All our products are manufactured in the USA.

Additionally, our high quality products are widely accepted in many different sectors such as residential and commercial building construction, healthcare, steel buildings, and government among many others.  We stock the majority of our products in our centrally located warehouse in Texas and ship out same day which allows for most orders to be delivered anywhere in the US within 1-3 business days.  We offer excellent quality products are great prices.

3.  What is the difference between Foil & Metalized?

Radiant barriers and reflective insulations must have a highly reflective surface to be effective. In general, there are two ways of creating a reflective surface.

The oldest and most proven method of creating a reflective product is to use an actual thin sheet of aluminum which is laminated to a substrate or “scrim” material. These products are typically called FOIL as they use a foil type material.

The other method which is fairly new to the radiant barrier industry creates a reflective surface using a metallization techniqe. This method of metallization is a process which applies a very thin reflective coating (typically 99% liquid aluminum) to the outer layer. Essentially it is a reflective paint that is sprayed to the outer layer of the barrier.

This new method of metallization was introduced to the radiant barrier industry recently as a way to meet the newest fire test requirements adopted recently by the ASTM. When the new test methods were initially introduced, the FOIL products failed the new test. It was then found that using a metallization process would allow the product to pass the testing. However, we've recently developed a FOIL product that PASSES the new fire test and does so with a perfect 0 flame spread as does our metalized version.

Our metalized products have more of a “plastic” feel to them.  Our foil  products  feel more like holding a thick sheet of aluminum with a rigid firm feel.

When determining which product to use, it's really just a personal preference at this point as both our metalized and foil are both excellent quality products that reflect 95-97% of radiant heat, are extremely durable and pass the required fire test. We have users that love both versions of our products.

For more details, please review the detailed product specifications for each product.

4.  For an install in an existing home in the attic, should I staple the radiant barrier up or lay it over the attic floor?

In an existing home, there are two installation methods to "retrofit" a reflective product in an attic; stapled up to the underside of the roof decking/rafters and laid over the attic floor. Both of these methods have been proven effective however, there are advantages and disadvantages with each.

The layover method is the easiest install as it takes much less time and does not require stapling or require the use of a ladder.  When installing in this manner, a breathable (perforated) radiant barrier is basically rolled out over the attic floor with each section overlapped by one to two inches.  There is no reason to tape the seams or staple the product down unless you are covering decking and plan to walk on it in the future.  This method will block the heat from penetrating into the living space below during the warmer months as well as hold the heat this is trying to escape the living space in the cooler months. 

There are some concerns with the layover method which are based upon the opinion of the Department of Energy/ENERGY STAR program.  The first concern involves the potential of dust accumulation on the top of the radiant barrier's surface over time and how this would affect the performance of the radiant barrier.  The second concern involves the potential for condensation to collect underneath the radiant barrier although a breathable (perforated) radiant barrier is utilized.  The potential condensation concern is a very rare occurrence and more probably in the northern climate zones.  Because of these concerns, our preferred method of installation is to staple the product up under the roof rafters.

The staple-up method may take more time but the concerns of dust accumulation and condensation are completely avoided with this installation method. The staple-up method is much more effective for the warmer climate zones as most homes have A/C duct work in the attic.  By installing the radiant barrier underneath the rafters, this dramatically lowers the temperature of the entire attic space keep the A/C ducts cooler.

5.  Can I install a radiant barrier between my decking and asphalt shingles?

NO, this will not work. Any reflective product needs at minimum a ¾” airspace in order to work. Without this airspace, the product acts as a conducting material and transfers all the heat from the roofing material into the attic. We receive calls all the time on this issue and in many cases a potential customer had been told by a roofing contractor that this installation method would work, unfortunately either the contractor is miss-leading the consumer or he just does not understand how reflective products work. Please see this page for more information about how radiant barriers work.

6.  Are your products made in the USA?

YES! All our products are manufactured in the United States. We receive many calls on this subject where people have been told by some competitors that there are no companies selling radiant barriers that actually manufacture in the US and that they are all made off shore and boxed in the US. This may be the case for some suppliers, but not us. It is true that some of our raw materials are bought outside the US, but ALL manufacturing is here in the USA. Typically the companies making these claims are buying from Asia and want to convince consumers their products are the same as ours.

7.  What is the issue with the Fire Ratings?

This is a very popular question so we've devoted an entire page to the E84-10 & E2599 fire rating subject.

8.  What is the difference between single bubble and double bubble?

Because there is little difference between single and double bubble r-values for the product itself, we recommend our single bubble products. We stock our single bubble products and ship same day if the order is received by 4:00 central time. If you are looking for a double bubble product, please contact us for pricing.

9. Do I have to have other insulation in my attic for a radiant barrier to be effective?

No; a radiant barrier works independently of other insulation products. 

If you currently have no insulation in your attic space, you will most likely see a greater reduction in your utility bill by adding a radiant barrier than someone adding a radiant barrier to an attic full of existing insulation.

This does not mean that you don't need other insulation products in your attic.  Mass insulation, like fiberglass insulation, blown-in cellulose, and rock wool, work to protect you against conductive and convective heat flow and therefore, when used in conjunction with a radiant barrier, give you the best overall protection for reducing the transfer of radiant heat.

10. My rafters are 24" apart. Do you carry a 24" wide product?

All our radiant barrier are 48" wide and most commonly installed across the rafters spaces therefore, it doesn't matter how far apart the rafters are.  If for some reason you want a 24" section for installs, you can quite easily cut an entire roll of radiant barrier in half with a hacksaw resulting in two 24" mini-rolls.

For more frequently asked questions, please see our FAQs.  

Top Unfounded Myths

1. Will a radiant barrier "cook my shingles" if installed under the rafters?

This is a very common myth (intentional scare tactic) used by competing product suppliers.  The answer to this question is NO, a radiant barrier will NOT "cook" your shingles. A radiant barrier may cause an increase in shingle temperature by 2 to 5 degrees Fahrenheit on a hot summer day.  Given that shingle temperatures on a hot date are in the range of 160 to 190 degrees, this small increase is negligible and does not accelerate shingle degradation.  Although roofing manufacturers were concerned about shingle failure in the years when radiant barriers were first used, it is no longer a concern. 

Read this roof shingle temperature study for more details.

The Florida Solar Energy Center also conducted a study on the use of radiant barriers under shingled roofs and found that properly installed, radiant barriers do not void the warranty of shingles.

2. Will your product de-laminate over time?

This has become a favorite scare tactic from some competitors outside our industry as well as some within our own industry. The truth of the matter is that a high quality laminated product such as ours will not delaminate. Radiant barriers have been in use for over 30 years and most all high quality products installed years ago are still laminated and working fine. Most recently new advanced adhesives ( glues) are being used to assemble airplanes rather than screws. If adhesives can be used for planes, we can assure you it can laminate a building material.

In addition, our products have been tested by an independent testing laboratory using ASTM criteria for Adhesive performance and Pliability performance.

  • The pliability test criteria is tested at 70°F ± 5°F & 50 ± 5% Relative Humidity Results: No Cracking or Delamination
  • The adhesive performance is tested at 180°F ± 5°F & 50% Relative Humidity Results: No Bleeding or Delamination
3. I have heard that bubble products loose air over time and lose their effectiveness. Is this true?

This is a fairly new myth that was recently created from a competing product manufacture and it is completely false. This is their way to redirect the customer to their foam based product which is significantly more expensive than the equally performing reflective bubble insulation products in the market today.

Our Reflex-Air™ bubble insulation products are industrialized products, not basic packaging bubble wrap, that are manufactured to last and maintain the enclosed air space. The independently enclosed bubble layers are sealed with multiple layers of polyester creating closed air bubbles which prevent the loss of air. We are so confident in our products that we offer a 10 year warranty. All our reflective bubble insulation products are available in 16", 24", 48", 72", and 96" widths and of varying lengths. We offer straight edge, staple tab and tape tab versions.

4. I was told that radiant barriers are for new construction only and cannot be retrofitted in an attic.

This is not true; actually a majority of our radiant barrier sold is installed into existing homes by either home owners or through our dealers.

5. If I install this in my attic, will it block my cell phone coverage?

It is very doubtful you will lose your cell coverage. If you think about how cell towers transmit signals, most all the wireless signals come through the walls and windows of a building or home. It is true that a small portion of the signals can be weakened a little by the radiant barrier, but not enough to affect your signal.

6. Will your aluminum foil insulation products lose their reflectivity over time because of oxidation?

No, a high quality aluminum foil insulation products reflectivity is NOT AFFECTED by the natural oxidation process.

All aluminum surfaces oxidize when exposed to oxygen and this oxidation process produces a CLEAR layer over the top of the surface of aluminum. This clear layer will increase in thickness to a point where the oxygen in the environment can no longer continue the oxidation process.

High quality aluminum foil insulation products, such as RadiantGUARD® Ultima do not lose reflectivity because there is a significant amount of aluminum remaining after the completion of the oxidation process.

For detailed information on the research and findings on the oxidation of aluminum insulation, please visit this radiant barrier oxidation technical study.