So you are doing your due diligence by researching whether or not radiant barrier is a scam is true. Radiant barriers installed in existing homes have generated a lot of confusion and controversy. As energy auditors we know that too often energy saving claims have become grossly bloated from 20% of air conditioning bills to 20% of your entire electricity bill, which is quite different. Consider this, if heat gain into a home with good insulation is only 15% from an attic, how can a radiant barrier reduce the energy bill by a minimum of 25%? It’s impossible!
A homeowner today should also be aware that there is no one energy saving upgrade that will create a high performing home in terms of comfort, lower air conditioning bills and air quality. Homeowners should therefore be considerate of alternative recommendations such as duct sealing and air conditioning tune-ups to work in conjunction with a radiant barrier. The Department of Energy has performed studies and written articles on radiant barrier foil and has concluded it works by reducing attic temperatures and thus reduces heat gain into a home. What is the problem then? We will cover that later but first I’d like to go over the different types of radiant barriers on the market.
Radiant barrier paint, radiant barrier chips and radiant barrier foil are the three types of radiant barriers. We do not support the installation of radiant barrier chips or radiant barrier paint. Radiant barrier paint can be diluted in the field with water and will lose its effectiveness when applied. I’ve seen many houses where the radiant paint looks more like gray paint rather than a reflective paint, which is a sign of dilution. Radiant barrier paints also has lower performance standards with higher emittance values and lower reflectance values than traditional radiant barrier foils. Radiant barrier chips are not recommended because installers usually do not install them with enough density to cover the entire surface area of the attic and they can be easily moved. Besides the radiant barrier paint and chips, we do support the use of radiant barrier foils.
The radiant barrier foil comes either in single or double sided; breathable with ventilation holes or it may not have any ventilation; or has a foam core with some insulation value to it. By itself, a radiant barrier has no insulation value because it reflects radiant heat from radiation, unlike insulation that slows down the transfer of heat through conduction. Radiant barriers should also be installed along the roof trusses whenever possible compared to laying along the attic floor.
How Much Heat Comes From The Attic?
Surprisingly, not as much as you would think. According to APS and SRP studies only 14% - 20% of your utility bill is driven by heat gain from the attic, most of it comes from windows. I can also validate these findings from my personal experience modeling hundreds of homes in the Phoenix area under the APS energy audit program and SRP energy audit program. On a side note, there is up to $1,000 in APS rebates and SRP rebates available for home energy upgrades. Visit the APS Energy Audit Program and SRP Energy Audit Program for more information.
If There Is No Radiant Barrier Scam, Then Why Do Most Fail?
The problem just like a driving a Prius with a hole in the gas tank - is how it is installed and a lack of understanding of what homes it will have an effect on and what homes it will do nothing for. Most radiant barriers are sold by a sales consultant who is not a certified energy consultant and will sell radiant barriers to every home they go to and over promise on their performance. A comprehensive energy audit should be performed with a blower door test and by a BPI Certified auditor to test and identify the real causes and solutions to reduce energy bills and eliminate hot and cold rooms. In an attic with R-38 insulation, the heat gain into the house is small and is approximately 80% conduction and 20% radiation. The radiant barrier is going after that 20% of heat gain which may not be the most cost effective option. There are certain cases where a radiant barrier would be a good choice for your home, but Green ID will not sell or install radiant barriers where it is not needed or better options exist.
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