Radiant Heating and Radiant Barriers

If you have a radiant heat system, radiant barrier foil is an ideal way to maximize your radiant heat efficiency. 

Radiant heat is heat that is transmitted from a heat source through space and a radiant barrier is designed to reflect that heat towards your living space.

Radiant barriers are made from materials that are poor at absorbing heat but excellent at reflecting it. A radiant barrier is usually a thin sheet or coating of a highly reflective material, mostly aluminum. An effective radiant barrier must reflect 97% of the heat and in order to perform correctly, the reflective side must be open to an air space.

By using radiant barrier foil you can substantial increase your energy savings especially since this foil barrier can reflect so much heat back to its source. By using a foil barrier you will keep your home far warmer than without a radiant barrier.

A few things are important to look out for when buying a radiant barrier. If you’re doing the installation yourself, you should select a tear resistant radiant barrier so your installation will be easier. The best way to test the strength of the radiant barrier is to take a small sample and try to tear it by hand. If it rips apart, chances are it will tear easily and make your installation difficult.

The types that don’t tear easily usually have a woven mesh that is laminated between two sheets of foil. Other types of radiant barrier use what is called, a " bubble-pack" between the foil sheets, giving the radiant barrier some added strength.

Another thing to check would be the flammability rating. You should select a radiant barrier that has a Class I USB (Uniform Building Code) or a Class A NFPA (National Fire Protection Association) flammability rating. To make sure, you can always ask your local fire department or building inspector to review your selection or recommend an appropriate product.

Be aware that radiant barriers can also be used as vapor barriers, which prevent moisture from passing through them. So depending on where you are using a radiant barrier will determine what kind you use. You don’t want warm air passing through it onto a cold surface and then condensing, this could cause problems.

For installation, place the radiant barrier, foil-face up under a sub-floor about 1 to 2 inches below the radiant tubing.

To receive the best efficiency and comfort from your radiant heating system some basic rules should be followed; all of your exterior rim joists should be insulated; and insulation should be stapled to the bottom of your joists under the radiant barrier.


Also, keep in mind that radiant in-floor heat will not work properly until the joist space is closed.

While radiant barriers are certainly not new on the market, they are an inexpensive yet effective way for homeowners to save energy and money. Radiant barrier materials are continuing to improve and they are becoming widely available throughout North America.

With a radiant heat system, a radiant barrier will reflect the heat back into the home, heating your home much more efficiently.