One of the most commonly asked questions by anyone first looking at Radiant Barrier insulation systems is which one is better and most cost effective, paint or aluminum foil radiant barrier? The answer is very simple when you look at the numbers, product and application for each.
When looking at installing radiant barrier insulation in your attic, you will have three basic options. You can staple a traditional Radiant Barrier Foil to the rafters, lay it over the floor in your attic, or spray a paint product to the underside of the roof decking. (**scroll all the way to the bottom for warranty information on your shingles with some radiant barrier products. Our application methods will not damage your shingles.)
According to RIMA (Reflective Insulation Manufacturer's Association) there are many misconceptions when it comes to radiant barriers. One is Ceramic paints are as effective as radiant barriers.
One of the major misconceptions in the insulating paint field is that “ceramic paints” can be used on the interior like an IRCC to reduce attic temperatures and lower cooling energy costs. However, the application of a “ceramic paint” to the underside of roof sheathing may increase the attic temperature because “ceramic paints” typically have a higher emittance than the sheathing deck. If a paint does not conform to ASTM C 1321, “Standard Practice for Installation and Use of Interior Radiation Control Coating Systems in Building Systems”, it should not be considered for interior applications in the attic.
In looking at the best product, you also need to look at the application of the product in your attic.
Our RADIANT BARRIER product is stapled to your roof rafters for full coverage, leaving at least a 6 to 8 inch air space between the radiant barrier and the roof decking covering all areas with our unique installation methods. We install into tunnels and seemingly impossible areas to reach that even the paint wands can not get to with our unique engineered installation methods. This air space will allow proper airflow and enhance the radiant qualities of the aluminum helping the blown-in insulation not absorb as much heat and exhausting moisture completely. We also have full coverage of the roof joists and can apply the product to a bedroom or game room wall that backs to the attic to prevent a room from having extreme temperature fluctuations. When you staple it to the rafters, it prevents your air conditioner and ductwork from absorbing the attic heat thus delivering cooler air into the home. It will also help your air conditioner not have to work as hard increasing the life of your air conditioner units. The Energy Attic Radiant Barrier will not be less than 97% reflective because it is a solid aluminum product. Because Energy Attic Radiant Barrier is double sided it will also work in the winter months reflecting radiant heat back to the warm living areas but still letting the moisture and convected heat leave through the roof vents.
Laying foil radiant barrier over the attic floor is not recommended in Texas in most applications.
A few reasons not to lay aluminum over the attic insulation floor:
According to the Department of Energy - Paint products are NOT a true "radiant barrier". They do not work as advertised misleading the consumer. Each particle of aluminum powder is encapsulated by paint therefore not allowing the aluminum powder to form a solid sheet of aluminum barrier. The aluminum particles can not stop the heat because the paint super heats and bypasses the aluminum particles. Even if it did help a little it is typically applied only to the roof decking leaving the joists and rafters unpainted. All the exposed joists will continue to radiate intense heat inside the attic. It will also vary depending on how heavy the paint is applied and the type of wood being sprayed without primer. The paint also gets on everything exposed in the attic and causes airborne contaminants that get into the home.
The U.S. Federal Trade Commission (FTC) defines "home insulation" as "any material mainly used to slow down heat flow" (16 CFR Part 460.2). ENERGY STAR considers insulation to be products or materials that meet the FTC's definition of "home insulation" and are used to insulate a whole wall, ceiling, or floor. These products include, but are not limited to: fiberglass, cellulose, mineral wool, whole-wall spray foam, rigid foam board, cotton fiber batts, and foil radiant barrier products.
This means that paint products do not qualify for the energy tax credits for 2009 or 2010.
When you are looking at any product offering energy savings, check to see if it is Energy Star-rated.
To help answer the question of foil versus paint, we also need to look at the issues of the overall effectiveness of each type of product. The effectiveness of a radiant barrier is measured by how much heat it reflects and emits to the air space below. You want the emittance value to be as low as possible. The emittance value of the Energy Attic Radiant Barrier is .03. This means it reflects 97% of the radiant heat in your attic only allowing 3% of the radiant heat into your attic. The paint products shown below all have Product Emittance values much higher than our products. As you can see, they still allow 23% to 90% of the radiant heat into your attic! That is a lot of heat gain and loss compared to our 3%. This means the very best paint product is advertised to reflect "up to" only 77%** of the heat. Please refer to the chart below to see some of the most common brands of paint products and their emittance values.
As per the Department of Energy – a true radiant barrier must have the emittance value of .10 or less. None of the paint products meet these criteria and therefore, are not true "radiant barriers".
|All EnergyAttic Radiant Barrier products (solid aluminum) .03|
.95 to .23**
.95 to .23**
.95 to .23
.95 to .36
.95 to .57
.95 to .59
|Formula A Barrier Coat #85|
.95 to .66
|Formula B Barrier Coat #85|
.95 to .70
.95 to .86
|Barrier Coat #233|
.95 to .89
.95 to .89
.95 to .90
**The paint product has emittance of .23 to .90 in lab tests only compared to EnergyAttic Radiant Barrier at .03. Even the emittance ratings are questionable because paint which encapsulates the aluminum flakes has an emittance of .95. So how can any of the paint products have less than .95 emittance?
Another thing to consider when installing some radiant barrier products is the affect it will have on your shingles and the installation method in which the radiant barrier is applied. Our installation method does not cause damage to the shingles over time simply because of the air gap that is left between the roof deck and the radiant barrier.
According to one manufacturer the Limited Warranty is reduced where a radiant barrier has been installed with or without ventilation directly below the deck or when insulation is installed immediately beneath an acceptable roof deck system. They go on to say it could reduce your warranty period by up to 10 years. We can provide you with a copy of this manufacturer's warranty but we would also recommend that you check with your roofer to verify the warranty restrictions. If you would like a copy of this, please click on the request a quote and let us know where to send it.