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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:
What is a radiant barrier?
A radiant barrier is made of highly reflective material and is typically reinforced with a middle fabric layer making it puncture and tear resistant unlike basic kitchen foil.
Unlike mass insulation that merely slows down or resists the transfer of heat, a radiant barrier BLOCKs the transfer of a large percentage of radiant heat (at a minimum 90% as prescribed by the official Department of Energy definition of a true radiant barrier).
Radiant barriers BLOCK radiant heat by reflecting it back towards the direction it came as well as REDUCE convective heat by acting as a blockage against convective air flow.
With a radiant barrier properly installed, you can significantly reduce the amount of heat that common insulation materials merely slow down thereby maximizing the efficiency of your existing insulation materials making your living space more comfortable while reducing your overall energy utility costs.
What is radiant heat?
An example of radiant heat is the heat you feel on your skin when you walk out from under a shelter into the direct sunlight.
Exactly how does radiant barrier work?
Simply put, a radiant barrier reduces the transfer of a large percentage of radiant heat in one of two ways:
a radiant barrier REFLECTs a large percentage of radiant heat that strikes it surface across an air space back in the direction from which it came, and
it EMITs a very small percentage of radiant heat from its own surface facing an air space.
Noticeably above, the words "air space" are used in describing both methods a radiant barrier utilizes to reduce the transfer of radiant heat. For a radiant barrier to be effective in any installation, and air space of at least 3/4" of an inch must exist on at least one side of the radiant barrier.
Is a radiant barrier the same as basic kitchen foil?
Basic kitchen foil is not the same as a RadiantGUARD radiant barrier. Basic kitchen foil is much thinner than a typical radiant barrier product and lacks the middle scrim layer that adds durability in the form of puncture and tear resistance that exists in RadiantGUARD radiant barriers. Our radiant barriers are almost impossible to tear by hand unlike typical kitchen foils.
More importantly, the shiniest of kitchen foils only reflects an average of 88% of the radiant heat whereas RadiantGUARD radiant barriers reflect a much higher percentage of 95- 97%.
Also, our radiant barrier foil insulation products are available in a perforated version to allow moisture to pass through reducing condensation issues. Kitchen foil is not perforated and therefore, traps moisture.
What's the difference between a radiant barrier and the "so-called radiant barrier paints?"
There's a big difference! A true radiant barrier reflects 90% or more of the radiant heat. The most effective reflective paint reflects only 78% of the radiant heat.
Such reflective paints are NOT radiant barriers as they don't meet the minimum 90% reflectivity requirement set forth for radiant barriers by the Department of Energy (DOE).
What is the difference between an aluminum foil radiant barrier and a metalized radiant barrier?
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 metalization techniqe. This method of metalization 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 metalization 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.
What is the "R" value of a radiant barrier?
Radiant barriers do not "absorb" heat like mass insulation (fiberglass, cellulose, foam, etc). Instead, our RadiantGUARD radiant barriers, with their highly reflective surfaces, reflect 95-97% of the radiant heat that hit their surfaces and therefore, have no R-value rating. Installing a radiant barrier between the heat source (sun) and an existing R-Value rated insulation will improve the effectiveness of the R-Value rated insulation. Why? Because only 3% of the radiant heat is now hitting the R-Value rated mass insulation thereby extending the amount of time it has to absorb heat before becoming saturated and passing the heat into your living spaces.
How will a radiant barrier keep my home cooler?
All materials have some degree of reflectivity and re-transmission of heat. The shingles, tar, and plywood comprising a typical roof absorb radiant heat from the sun and conduct this heat through to the plywood decking. Because plywood decking emits approximately 82% of its heat, your attic gets hot.
A RadiantGUARD radiant barrier stapled to the underside of the decking or rafters would emit only 3% of the heat from the plywood decking resulting in an overall cooler attic which means less heat to enter your living spaces resulting in lower utility bills.
Do I need 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.
I already have plenty of insulation in my attic. Do I really need a radiant barrier?
Regardless of how much insulation you have in your attic, adding radiant barrier foil insulation will save on your heating and cooling expense, and keep you much more comfortable.
Quotes from notable studies on radiant barrier:
"A radiant barrier system can stop 95-97% of the thermal radiation across an attic space. If it is not stopped, that radiant energy would be absorbed by the ceiling insulation and eventually be transferred to the living space below." "The Solar Collector," Quarterly Newsletter of the Florida Solar Energy Center.
"The heat storage capacity of reflective insulation is low. As a result, it does not store heat during summer days, only to pass it on down into the rooms of the house from the attic at night when coolness is most apt to be desired from the point of view of sleeping comfort."; "Progressive Architecture," Nov. 1949, Page 76.
"Reflective foil retrofitted to fiberglass insulated . . . buildings is demonstrably effective in reducing heat loss . . . Installation of foil in uninsulated buildings would show even more pronounced reduction in heat loss." "Effects of Reflective Foil On Heat Loss in Attic Floors and Metal Building Installations," Northeastern Illinois University, Prof. Charles Shabica, May 20, 1986.
Will dust accumulate on a radiant barrier and reduce its effectiveness?
This very issue has been studied by several research institutes.
An exhaustive test performed by James R. Hall, project engineer for the Tennessee Valley Authority concluded that "... dust appeared to have little effect on the effectiveness of the radiant barrier. The percent reduction in ceiling heat flux was remarkably similar to that of a radiant barrier with no dust. He stated that a radiant barrier's performance "...may not degrade nearly as much as would be expected from the significant increases in emissivity caused by small amounts of dust." Click here to read the report - summary conclusion is on page six.
How much money can I expect to save on my utility bills if I install a radiant barrier in my attic?
Although RadiantGUARD radiant barriers BLOCK 95-97% of radiant heat, your utility bills savings will vary because some homes are more energy efficient than others and because of other forms of heat flow in a building structure that contribute to the total cooling (or heating) load. Data varies by region.
Direct quotes from a radiant barrier study performed by the Tennessee Valley Authority help to point out the heat transfer reductions you can expect although heating and cooling economic savings will vary based on other types of heat flow and local climatic variations:
"All the radiant barrier configurations tested yielded sizable percent heat transfer reductions (ranging from 16 to 40 percent) and statistically significant reductions in summer attic heat transfer compared to the non-radiant barrier case. Also, as the ambient temperature increased, the reductions also increased."
"The radiant barrier configurations provides statistically significant winter attic heat transfer reductions in many, but not all, situations. The percent reductions during night hours and during below 35 degree F conditions, when heating loads are highest, are usually sizable (from 6 to 23 percent) and the differences between the radiant barrier configurations and the non-radiant barrier case are often statistically significant during these conditions."
Note: Note: The above study was conducted in Chattanooga, Tennessee and references radiant barrier performance tests when used in conjunction with R-11 and R-19 insulation however, R-30 is the least amount of insulation permissible under 2006 IECC. R-11 and R-19 are not reasonable baselines in 2009.
Are radiant barriers tested by qualified independent testing agencies or governmental agencies?
The Florida Solar Energy Center at Cape Canaveral has tested radiant barriers in both small scale laboratory and full scale building models. Their results indicate that radiation barriers provide significant resistance to heat transfer.
Current tests conducted by the Tennessee Valley Authority and the University of Mississippi support the findings at the Florida Solar Energy Center.
Northeastern Illinois University conducted winter tests in residential and commercial structures using infra-red thermograph photography. The photos showed significant resistance to heat transfer over the regular insulation.
Reliable individual brands of radiant barrier products are tested by the American Society for Testing and Materials (ASTM) and result in verified and uniform product specifications that can be trusted when researching a radiant barrier to purchase.
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 (BBB) rating and is a manufacturing member of the American Standards Testing Methods. 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.
All our products are manufactured in the US, period. There are some competitors making false claims that no company manufactures a radiant barrier in the United States. They claim the products are made off shore and boxed in the US. This may be the case for some companies but NOT US.
We guarantee all our products are made in the USA and also meet the ASTM C1313 (our radiant barrier) & ASTM C1224 (our reflective insulation) requirements.
All our products are comprised of the highest quality products and have undergone rigorous quality assurance inspections and certification testing to ensure you receive the best products available in the marketplace.
Because of our strong commitment to the advancement of the radiant barrier and reflective insulation technologies, we do not offer any "factory-seconds" or "blemished reduced-price" products ensuring the consumer that RadiantGUARD products are the best products for their applications.
Top Myths / Misconceptions
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.
I heard if I install a radiant barrier in my attic, I will lose my cell phone signal.
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.
Does an aluminum foil insulation product lose its 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 our RadiantGUARD Ultima-foil 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.
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.
Will a radiant barrier 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
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 5 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.
Are your products "really" 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.
Do I need a radiant barrier or bubble insulation for my my attic?
There is no need to purchase and install the more expensive reflective bubble insulation for your attic space as it will end up performing exactly the same as a radiant barrier which is almost 1/2 the cost. However, you certainly can install the reflective bubble insulation in your attic space but stapled to the roof decking or underside of rafters ONLY. You cannot lay a bubble insulation product over the attic floor because it is a vapor barrier (not perforated like our radiant barriers) and will trap moisture that rises from your living space thereby causing condensation and potentially causing water damage in your attic space. If you want to install one of our products on your attic floor, you must choose our Ultima-foil breathable radiant barrier.
Do I need a perforated or solid radiant barrier in my attic?
A radiant barrier used in the attic floor application MUST be perforated to allow water vapor from your living space to to pass up through it and be carried out your attic via your attic ventilation. This is necessary because, during the winter, if there is no effective vapor retarder at the ceiling, water vapor from the living space may condense (and even freeze) on the underside of a solid radiant barrier lying on the attic floor and cause water damage to the ceiling and any existing attic floor insulation. Why? Because warm moisture laden air always moves towards cooler air and will condense on surfaces trapping the air if it is not a perforated material allowing the moisture laden air to pass through it and out the building structure.
Read more here to determine if you need a breathable or solid radiant barrier.
How much radiant barrier do I need for my attic space?
In order to purchase the right amount of RadiantGUARD® radiant barrier products, you need to know the method of installation you intend to follow as well as the square footage of the area you intend to protect from the radiant heat.
Laying Over Attic Floor
If you intend to lay the radiant barrier over the attic floor, you need to know the square footage of the area of your attic.
If your attic covers your entire home and your home is one story, then the square footage area of your attic should be the same as the noted square footage of your home based on your last appraisal.
If your home is a two stories, you will need to know the "footprint" square footage of the second story which the attic covers.
Stapling to Underside of Rafters
If you intend to staple the insulation to the underside of the roof rafters, you need to know the roof area square footage calculated as follows:
Multiply the length and width of the roof to find the footprint square footage.
Based on the ***slope/pitch*** of your roof, multiply the footprint square footage by the appropriate factor listed to the right.
The resulting number is the roof area square footage. You should purchase enough material to cover this square footage amount keeping in mind that each radiant barrier piece is to be overlapped by 1-2 inches.
Note: If you have a gable or hip roof, you will need to measure each section separately using this technique and the add the amounts to get the total roof area square footage. If you intend to cover the gable ends as well, don't forgot to include those in your calculations.
**** "Slope/pitch" = the number of inches a roof rises ("rise") for every foot of horizontal travel ("run".) Communicated as inches of rise:12 inches of run
How do I install radiant barrier?
Please see our Radiant Barrier Installation page for the most common radiant barrier installation methods. Our instructions can be easily reviewed online, printed, and even saved to your local PC for later reading.
When installing in my attic space, should I lay the radiant barrier over the attic floor or staple to the underside of the roof rafters?
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.
Do I need to tape the overlapping seams when I install the radiant barrier in my attic?
Taping of seams is generally only done when using a solid radiant barrier or bubble insulation and you're trying to create a vapor barrier. We recommend using a perforated radiant barrier in the attic and therefore, there is no need to tape any seams. However, a solid radiant barrier or bubble insulation can be used on the attic rafters if desired and you can tape the seams for aesthetics or to create a vapor barrier.
If I install the radiant barrier partially under the rafters and partially over the attic floor, will I see benefits?
Yes, you will receive some benefits, HOWEVER, you won't receive the maximum benefit provided when you fully install to either the rafters or attic floor. Why? Simply because you're leaving open spaces for heat to penetrate through the roof and then through the ceiling to the living spaces below.
When you install to the attic rafters in all parts of your attic, you block the radiant heat from heating up your attic space thereby eliminating it from entering your living spaces. If you install to the attic floor in all parts of your attic, you block the heat within your attic from entering your living spaces.
Some people gain even higher savings by fully installing on both the attic rafters and the attic floor. The radiant barrier on the attic rafters blocks 95-97% of the radiant heat from the roof decking and then the radiant barrier on the attic floor blocks 95-97% of the radiant heat that made it through the attic rafters location.
What size staples work best with the radiant barrier and bubble insulation?
We recommend 5/16" staples.
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.
Is there a top and bottom side to your radiant barrier and which way should I face toward the heat?
All our radiant barriers are double-sided and exactly the same therefore, it doesn't matter which side faces which direction.
My rafters are 24" apart. Do you carry a 24" wide product?
All our radiant barrier produtcs 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.
Order Related Questions
When will my order ship and when will I receive it?
All products listed in website (unless otherwise noted on the product detail page) are stocked and shipped the same day if the order is placed before 4:00 pm CST. All orders are shipped via UPS and arrive at domestic US locations within 1 - 5 business days.
I received a shipping tracking number but UPS.com doesn't show a current status of my package(s).
UPS.com will show a current shipping status once they actually pick up your order from our warehouse and scan it into their system. If you currently do not see a shipping status on the UPS.com website, wait until the end of the next business day after your order was placed. You should be able to inquire on the shipping status at that time on the UPS.com website. If you still see no status, please call us toll free at (866) 528-8412 option 1 and a customer support representative can assist you.
How do I cancel an order?
For assistance in cancelling your order, please call us toll free at (866) 528-8412 option 1 and a customer support representative can assist you.
Can I return any unopened rolls of RadiantGUARD radiant barrier or reflective insulation?
Yes, please see our Return Policy for information about the conditions under which we will accept a return for a refund.