What is the difference between radiant barrier and reflective insulation?

Author: Rosanna Aufderhar  |  Last update: Saturday, June 27, 2026

Radiant barriers are single sheets placed facing air spaces to reflect solar radiation and heat. Reflective insulation uses multiple layers and air spaces to create a thermal barrier that resists conductive, convective, and radiant heat flow.

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.

Is reflectix a radiant barrier?

The Reflectix® Radiant Barrier is an excellent upgrade for making a residential structure more energy efficient. The product is primarily installed in attic systems to reduce the transfer of radiant energy through the roof (resulting in lower attic temperatures) to the attic floor.

What is the downside of radiant barriers?

Simply put, the biggest possible problem with any kind of radiant barrier is dust. To understand why dust creates issues for all kinds of radiant barriers, it's important to understand how they work: Radiation transfers heat directly outward from an energy source.

What is reflective insulation?

Reflective insulation is a material with reflective facing—typical materials are foil-faced kraft paper, plastic film, polyethylene bubbles or cardboard. Radiant barrier insulation consists of a reflective material (generally aluminum foil) and can be combined with other materials in reflective insulation systems.

Insulating Walls with Reflective Foil Bubble Insulation

What are the cons of reflective insulation?

Cons:
  • Typically higher material cost than radiant barriers.
  • Needs multiple layers with air spaces to be effective.
  • Not ideal for open attic spaces.
  • Installation may be more complex than radiant barriers.
  • R-value decreases if compressed or making contact with surfaces.

How long does reflective insulation last?

As long as homeowners or certified attic specialists install them appropriately, radiant barriers last anywhere from 80 to 100 years. They are built to last and won't cause significant issues for decades.

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.

What is the average cost to install a radiant barrier?

Installing a radiant barrier costs $1,700 on average, but often ranges between $710 and $2,840 depending on whether your pro uses a foil or spray on type.

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.

Do you need an air gap with Reflectix?

For either a reflective insulation or a radiant barrier, an air space is required on the reflective side of the product. (Most Reflectix® products are reflective (shiny) on both sides.)

Does radiant barrier qualify for tax credits?

Eligible Insulation Products for Tax Credits

These products typically include fiberglass, cellulose, foam board, spray foam, and radiant barrier insulation. Proper installation is also key to qualifying for these valuable credits.

Does radiant barrier go on inside or outside?

The best way to make the heat convert to radiant heat is to make it cross an air space. This is why the radiant barrier is most effective when placed closest to the outside of the wall.

Does a radiant barrier add R-value?

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.

Which type of insulation is most effective?

House insulation: The most effective insulation

So having in mind that spray foam, fiberglass, and cellulose are the three mostly used insulation materials we made a comparison, and here are the results: Spray foam has by far the highest R-value, which is crucial for homes in extremely cold climates.

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.

Are radiant barriers worth the money?

Some studies show that radiant barriers can reduce cooling costs 5% to 10% when used in a warm, sunny climate. The reduced heat gain may even allow for a smaller air conditioning system. In cool climates, however, it's usually more cost-effective to install more thermal insulation than to add a radiant barrier.

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

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 thick should radiant barrier be?

In general, a radiant barrier is a reflective sheet which encompasses a middle reinforcement layer, referred to as a "scrim" that gives the product strength and durability. The thickness of a radiant barrier is usually between 3 and 5 mils (thousandths of an inch).

Does reflective insulation really work?

If you're planning a home remodel, reflective foil insulation is an option that you should really consider. It's highly effective at reducing heat transfer, easy to install, thin and lightweight, and can help prevent moisture buildup and condensation.

Can you use reflectix as a vapor barrier?

The product provides a vapor/moisture barrier, which is a strong contributor to the efficiency of the system. Reflectix® is available in convenient roll sizes which contributes to ease of handling and installation.

Can you use radiant barrier instead of insulation?

Aside from central heating and cooling, there are two different kinds of building materials commonly used to perform this task: insulation and radiant barriers. While both perform the same function—keeping your home at a reasonable temperature—the ways this is done vary greatly between the two.

Does reflective insulation keep heat out?

Unlike mass insulation, reflective insulation is able to keep heat in and reflect heat away. Mass insulation material like fiberglass and foam merely slow down the transfer of heat; they do not reflect heat away, nor do they keep heat in. Reflective insulation has the ability to control the transfer of radiant heat.

What is the longest lasting insulation?

Quick list of the estimated lifespan of popular insulation types:
  • Fiberglass: 15 years on average, with a possible 20-30 year span. ...
  • Cellulose: 20-30 years under the right circumstances. ...
  • Rock wool (also called “Mineral wool insulation”): 30-100 years with correct installation. ...
  • Rigid foam board: Up to 100 years.

What side of reflective insulation faces out?

Therefore, when installing foil faced insulation always fit the foil side where the temperature difference is greatest. So, any time you use a single side foil insulation, the foil needs to be facing toward the living space.

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