Is a Radiant Barrier Right for Your Home?

Radiant barrier is a great addition to attic insulation. Properly insulating your home is a great way to improve energy efficiency and comfort especially if you add a attic stairs cover. With all the different products available how do you know which is right for you? Here is some information to help you decide if installing a radiant barrier is a good idea for your home.

"Remember, with all properly installed insulation, the payback is certain...if you give it enough time. If you are moving in a year, only go with the basics that will improve the sale of your home."

What is Radiant Barrier?

Radiant barriers are made of aluminum and designed to reflect radiant heat from the sun. When installed properly, radiant barriers can reflect up to 95% of the radiant heat off the attic. The best way I have seen to describe this effect is it’s like putting your home or office under a shade tree.

"Installing a radiant barrier is like putting a shade tree over your attic."

There are many brands of radiant barrier available. Here are some tips to make sure you are using a good product:

Non-laminated radiant barrier - In a lamination process, the foil is either simply glued on or heat laminated to the plastic lining.  Both of these processes will eventually fail.  With some products you can peel the foil off the plastic right out of the box, with others you have to leave it in the attic for several years before you can easily peel it off.

Protective coating installed - Without this protection, aluminum will oxidize loosing its ability to reflect heat.  As the surface of the foil begins to oxidize, it turns cloudy.  If it continues and oxidizes all the way through, it will eventually turn clear.

Passes newest fire codes - make sure the radiant barrier passes all of the current codes including the ASTM E84 fire test under the new mounting method (ASTM 2599).

Radiant barrier benefits

The benefits of radiant barriers are both monetary as well as increased comfort. If your home or office are in the direct sun your roof radiates solar-generated heat to the insulation below it. The insulation absorbs the heat and gradually transfers it to the material it touches, principally, the drywall ceiling. This heat transfer makes your home less comfortable and can cause your air conditioner to run longer and consume more energy. A properly installed radiant barrier can block 95 percent of the heat radiated down by the roof so it can’t reach the insulation.

Roof-radiated heat also warms ductwork or mechanical equipment (air handler) found in your attic. The proportion of the total heat gain the ductwork represents, compared to heat gain to the interior of the house, varies depending on the amount of attic and duct insulation you have.

Should I apply radiant barrier to the attic floor?

According to the Department of Energy installing radiant barrier on the floor of the attic can cause problems. It may be an easier way to install radiant barrier but it can trap moisture between itself and the attic floor and cause the insulation to become damp. Damp Insulation may support mold growth and eventually will lose some of its R Value. If you decide to apply a radiant barrier to the floor of your attic make sure you air seal the attic floor with a closed cell spray foam prior to installation.

Will a radiant barrier damage my shingles?

I have had this question asked many times and I see no evidence that a radiant barrier damages shingles. The Florida Solar Energy Center has measured the temperatures of roof shingles above attic radiant barriers on hot, sunny summer days. Depending on the color of the shingles, their peak temperatures are only 2-5° F higher than the temperature of shingles under the same conditions without a radiant barrier. Since roofing materials are manufactured to withstand the high temperatures to which they are frequently exposed. A 2-5° F increase in peak temperatures that normally reach 160-190° F should have no adverse affect.

Radiant Barrier Cost

Since all buildings and there uses are different, this is a very difficult question to answer but according to research done by the Florida Solar Energy Center, you could save between 8-12% on annual cooling costs. If this is true, the cost of installing a radiant barrier is irrelevant given you stay in your home long enough to recoup your investment. The benefits of a radiant barrier extend beyond monetary and should make your building more comfortable as well. It is also a good idea to make sure the attic is properly ventilated. Installing a solar attic fan is a great way to save money and may qualify for a 30% tax credit.

About Michael Church

Michael Church has been involved with indoor air quality since 2005 and feels the unhealthy crawl space is one of the major problems causing poor indoor air quality.

13 Comments

  1. Ilda Victorica on January 27, 2016 at 5:32 am

    Fantastic post, added.

  2. Hot Attic Solutions in East TN | Save Energy on April 5, 2016 at 7:14 pm

    […] Install radiant barrier […]

  3. […] sure you do other things in the attic like insulate properly air seal and possibly even install radiant barrier like this rooftop where there’s no […]

  4. […] Install radiant barrier […]

  5. Larry Phillips on March 7, 2019 at 9:55 pm

    Can U Use Inch & Half White Insulation Board First Then Radiant Barrier. To Insulate The Attic Rafters. I Have 3 Eve Vents In My House.So I Was Going To Use Them For The Vents. So The Hot Air Can Go out

    • Kayla Wilson on March 8, 2019 at 8:56 am

      Hi Larry, it sounds like what your saying will work, just make sure there is an air gap between radiant barrier and insulation so the radiant barrier performs better.

  6. Whit Dodson on August 21, 2019 at 3:20 pm

    Michael,

    What if you’re not redoing the shingles? Can this be applied to an unfinished attic?

    Thanks.

    • Michael Church on August 21, 2019 at 3:22 pm

      Radiant barrier is installed inside the attic so yes, it is great for that as well. Great question.

  7. Henry Monroy on September 4, 2019 at 6:55 pm

    I’m at the begging stages of cooling my hot attic = hot house, what would you recommend (example: ridge vent, radiant barrier, attic fan) and in what order to install first?
    Thanks!

    • Michael Church on September 5, 2019 at 10:08 am

      Hi Henry, Congratulations on tackling your attic. My attic had none of the items you mentioned so I started with a ridge vent and made sure I had baffles installed to allow soffit air to be pulled into the attic. If the soffits are clogged it will try to pull from living space or gable but not all homes have gable vents. Then I did the solar attic fan. The fan actually uses the ridge to ventilate properly along with soffit. Then radiant barrier but I’d also air seal as much of floor as you can especially if you have recessed lights or a drafty attic access. Hope that helps and thank you for being a DIY Ninja.

  8. Ryan on September 23, 2019 at 5:28 pm

    Hi my question is why would you install a radient barrier under shingles or any other material that is supposed to protect your roof. Other than a metal roof that is already highly reflective given you choose a light color. My understanding is you wanna reflect the sun’s uv and ir rays from being absorbed by your roof. The radient barrier is underneath shingles so it’s being shaded and if it were to reflect any light rays they would be reflected back to the bottom of the shingles. Wouldn’t it be better to have a reflective roofing material that is exposed to the sun’s light directly?

    • Michael Church on October 15, 2019 at 8:29 am

      Hello Ryan. Installing radiant barrier under the roof decking is the preferred method versus on top of the insulation because it gives an air gap for the heat to escape to the ridge vent without creating a potential moisture problem between the radiant barrier and the attic floor. Radiant barrier should always be installed to work with the soffit and ridge vents. A reflective material on the roof may be effective but we honestly don’t have an opinion about it because that would be more of a roofing company product I would guess. For people needing a roof and wanting to install the material you mention, I think that sounds like a viable option. Radiant barrier is a way to get heat out of the attic for those of us that have a 25 to 30 year roof and are not looking to replace the roofing materials. Please feel free to share the reflective materials you are writing about in case any of our readers are interested. Thanks for the question.

Leave a Comment