How much does a radiant barrier reduce temperature in an attic?

Author: Aylin Frami  |  Last update: Wednesday, February 25, 2026

The tests to date have shown that in attics with R-19 insulation, radiant barriers can reduce summer ceiling heat gains by about 16 to 42 percent compared to an attic with the same insulation level and no radiant barrier.

How effective is a radiant barrier in an attic?

Radiant barriers are more effective in hot climates than in cool climates, especially when cooling air ducts are located in the attic. Some studies show that radiant barriers can reduce cooling costs 5% to 10% when used in a warm, sunny climate.

Does radiant barrier help with cold?

A radiant barrier reflects the sun heat from the roof and helps the attic remain at least 20 degrees cooler. This will make the whole house feel cooler and the air conditioner will work more efficiently. Regardless of regional climate and how drastic the seasonal changes are in your area, your local Dr.

How do I lower the temperature in my attic?

To deal with heat in the attic, consider adding extra vents and a roof exhaust to improve air circulation, and installing a solar fan for more active heat reduction.

What are the disadvantages of radiant barriers?

Moisture problems, air leaks, inadequate attic ventilation, dust accumulation, compatibility issues with existing insulation, and condensation are some of the common challenges associated with radiant barriers.

Why Is My Attic So Hot? How Can I Make My Attic Cooler? - AtticFoil.com Radiant Barrier

What is the R value of a radiant barrier?

What is the R-value of your radiant barrier? Radiant barrier on its own has NO R-value; R-value is attributed to materials slowing conductive heat. AtticFoil™ works to block radiant heat (97%) coming in to the attic by stapling it to the rafters, but it has no R-value.

What is an alternative to radiant barrier?

Another alternative to radiant barrier foil are the various types of foam insulation. What is foam insulation? Foam insulation most commonly comes in two forms: rigid and spray.

How do I make my attic not hot?

Ventilate The Attic Space

How else can you keep the attic cool? Remember the cool attic trifecta: radiant barrier, insulation, and attic ventilation. A complete ventilation system consists of exhaust vents, intake vents, and solar attic fans. Proper ventilation improves airflow and air circulation within your house.

What is an unsafe attic temperature?

If your attic temperature is consistently hitting 130 degrees or hotter, damage to your home and a high utility bill is very likely. You can keep a thermometer in your attic to check – it doesn't have to be an expensive one and will give you a better idea of how hot things really are.

Is 140 degrees too hot for an attic?

Ideally, the attic temperature should be close to the outside temperature, give or take 10 to 20 degrees. If your attic temperature is getting to 130 degrees or hotter, you can expect to see damage to your home. An attic can easily surpass this target in warm climates, getting as high as 160 degrees in the summer.

How much temperature difference between radiant barrier and attic?

Ideally, after you install a radiant barrier the air temperature inside the attic should probably be within 10 to 15 degrees of ambient temperature.

How much does it cost to install a radiant barrier in the attic?

When planning to install a radiant barrier, budget between $710 and $2,840, with the average homeowner spending around $1,700 to have a radiant barrier installed. Costs vary depending on which type—foil or spray-on—you choose and the size of your attic space.

Which is better radiant barrier or insulation?

Certified attic specialists recommend installing a radiant barrier. A radiant barrier reflects the sun's rays away from your home, preventing your insulation from becoming another heat source. It keeps your house cool and your cooling costs at bay.

Does radiant barrier keep cold out?

This type of insulation is most effective in warmer climates, but can also be used for comfort and energy savings in cold weather. The radiant-barrier insulation is attached to roof rafters, floor joists, and wall studs to reduce radiant heat flow, mostly from the outside in, but also from the inside out.

Does radiant barrier affect WIFI?

With Wi-Fi signals, unless the radiant barrier is between you and the router, there is unlikely to be any impact.

Does a radiant barrier need an air gap?

This is because an air gap provides an additional layer of insulation that helps to prevent heat from passing through the barrier and into the living space. If you are installing a radiant barrier, it's recommended to leave an air gap of at least 25mm (1 inch) between the barrier and the surface it's installed on.

How hot is an attic on a 100 degree day?

Thanks to the radiant heat affect, attic temperatures on a 100-degree day can reach 170 degrees or more.

Do radiant barriers work in attics?

A radiant barrier helps homes with HVAC ductwork in the attic by reflecting heat away from the system.

What percentage of heat is lost through attic?

Hot air rises, just like your energy bill will do if your attic is poorly insulated. A poorly insulated attic can result in 25% heat loss in fall and winter—that's 25 percent of your average heating costs going toward energy that won't even heat your home.

What is the ideal attic temperature in the summer?

The ideal attic temperature should be no less than 60 degrees in the winter and no more than 10 to 20 degrees above the outdoor temperature in the summer. If your attic temperature climbs above 130 degrees, you may start running into issues with your energy bill, as well as the integrity of your roof.

Why is my insulated attic so hot?

Insufficient ventilation

One of the primary reasons for hot attic spaces is due to poor ventilation. Without adequate airflow, hot air gets trapped, causing temperatures to soar.

Does attic temperature affect AC?

First, attic temperatures that put Death Valley to shame, in the 140-150-160-degree range, add lots more “heat load” to your system through your ceiling area, making it harder to cool your home. For most homes, this ceiling area is one of the largest factors in your home comfort, as well as equipment size.

What can I use instead of barrier?

Synonyms of barriers
  • fences.
  • walls.
  • barricades.
  • obstacles.
  • hedges.
  • blocks.
  • chains.
  • hurdles.

Can radiant barriers catch fire?

Aluminum covered radiant barrier products (like Original AtticFoil™) are pretty difficult to start burning, but once they flash (catch fire) the polyethylene scrim inside will continue to burn at a relatively slow rate.

How much does it cost to install a radiant barrier in an attic?

Radiant barriers cost between $710 and $2,840 for materials and labor, with most homeowners paying about $1,700. Your attic's surface area and the type, quality, and brand of materials affect the total material cost, while installation complexity, local labor rates, and other factors determine final installation costs.

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