How Understanding “r” Can Save You Money

When the weather’s brisk, it’s smart to wear a coat.

Your home needs the same kind of protection.

Just as a coat closet holds thin jackets and heavy jackets, different types of insulation, ranked by R-value, exist to keep your home comfortable and your electric bills affordable.

The R stands for resistance to the transfer of heat or cold. The number beside the R represents a rating that depends on the material, thickness, and density of the insulation. A higher R-value indicates more effective insulation. Multiple layers of insulation may be combined for a higher cumulative R-value.

But here’s where things get complicated.

Insulation resists the “conductive” transfer of heat, meaning the direct warming or cooling of the material. There’s another kind of transfer called “convective,” in which heat moves along with the air.

Using the comparison to coats, conductive transfer refers to how your body heat moves through the fabric of your jacket. But if the wind whistles up your sleeve or through a hole in your pocket, that’s convective transfer.

Most of the heat transfer in a poorly insulated and sealed house comes from convective heat transfer as air moves through leaks around doors and windows. Properly installed insulation can help reduce convective transfer, but weatherstripping around doors and other ways of plugging leaks are the most effective at reducing energy loss through convective heat transfer.

Installing insulation correctly can be tricky. It can be even harder figuring out whether you should pay more attention to stopping conductive or convective heat transfer. Call your local electric co-op for expert help on figuring out how to make your house as comfortable and affordable as possible.

Recommended R-values for Kentucky in new, wood-framed homes:
Wall cavity R-18
Attic R-49