Are Radiant Barriers Effective for Insulation?

Allie Ogletree
Written by Allie Ogletree
Updated December 14, 2021
large house with grey roof
Photo: Iriana Shiyan / Adobe Stock

Highlights

  • Radiant barriers cost homeowners $1,700 on average.

  • There are two types of radiant barriers: radiant barrier foil and radiant barrier spray coatings.

  • Depending on your climate, you could save up to $120 a year with radiant barriers.

  • Radiant barriers should be professionally installed to get the most out of your installation.

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On summer days, asphalt isn’t the only thing baking under the hot sun—your roof is, too. And if you don’t have proper insulation, your energy bills are likely to go through the roof. Here’s what you need to know about radiant barriers and whether or not they’re effective at keeping your house insulated.

What Is a Radiant Barrier?

aluminum insulation on ceiling of home
Photo: sutichak / Adobe Stock

A radiant barrier reduces heat build-up by reflecting solar energy coming through your roof. The barrier is a reflective material—usually either a lightweight aluminum foil or a painted-on reflective coating—and is installed in the attic ceiling or between the rafters of your home. The foil contains substrate materials (like cardboard, kraft paper, or fiberboards) to keep the barrier stable and durable. 

Radiant Barrier Foil vs. Spray Coatings

Radiant barrier foil and radiant barrier paint spray use aluminum as the primary method for reflecting radiation, but there are some key differences. As you consider which type of radiant barrier material to use, take these facts into account: 

  • Spray-on radiant barrier coatings are slightly less effective than foil, but they can cover more area or hard-to-reach pitches. 

  • The two types generally differ in emissivity or how much radiant energy passes through (less than 10%); however, radiant barrier foil reflects more incoming heat than spray coating.

  • Spray coating requires special protective gear to install, such as a VOC respirator and spray equipment; a skilled professional should apply the coating to ensure it covers evenly and correctly.

  • While radiant barrier foil is easier to install, it can be challenging to DIY if you don’t know the technical in’s and out’s of insulation installation. A pro may be better suited to tackle this one and ensure you reap all the benefits from a proper install.

Do Radiant Barriers Actually Work?

Applying a radiant barrier to your home can help reduce those scorching summer attic temperatures and give your HVAC system a bit of a break, but the barrier’s efficacy also depends on where you live. 

According to Energy Saver, radiant barriers alone can reduce your home’s cooling costs by up to 5% to 10%, with hot and sunny climates coming in at the higher end of that range than cooler climates or homes with a lot of shade. That’s around $120 in savings each year for hot climates and $15 in savings each year for colder climates.

You’ll want to combine your radiant barrier with the right type of insulation for the barrier to be most effective. Home Energy states that insulation absorbs and re-emits approximately 80% to 90% radiant heat, so combining insulation with radiant barriers can effectively keep heat out of your home.

How Much Does a Radiant Barrier Cost?

Before you get started insulating your house, factoring in the costs of radiant barriers can also potentially insulate your wallet. Radiant barrier costs between $750 to $2,800 or $1,700 on average to install. Prices vary depending on the size of your attic and roof pitch, with larger spaces costing more than smaller ones.

How to Install Radiant Barriers?

man Installing aluminum insulation on ceiling
Photo: coralimages / Adobe Stock

There are two ways to install radiant barrier foil: One way is to use a stapler to install the foil to the rafters of your roof. The other is to lay it over the insulation already in your attic. You’ll need to apply the foil strategically, with the reflective layer facing upwards, for the barrier to be most effective. If you’re not sure how to do this, find a local attic insulation pro to do the job for you.

If you choose to install spray-on paint, you can purchase it at your local home improvement store or order it online. However, as mentioned before, radiant barrier sprays may require the help of a pro who has the proper protective gear and equipment, knows how much to use, and can cover the area evenly. 

The Bottom Line

The best way to keep heat out of your home is to use both a radiant barrier film and insulation. At the same time, even installing a radiant barrier offers some protection against radiant heat and might be a good option for homes in hotter climates.

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