Insulation R-value matters

Q: I read in a column of yours that home insulation should have a “proper R-value.” What does that mean? — Doris L., Pittsburgh

A: R-value refers to the level of resistance to heat flow that insulation — from fiberglass attic insulation to pipe wrap — provides. Heat, of course, tends to radiate outward and upward, and in the winter especially, one wants to control how much of that heat escapes from the home and the water supply.

So, when choosing the type of insulation, the R-value is a more important consideration than the thickness or thinness of the insulating material. More is not necessarily better when it comes to home insulation. The R-value, the type of insulating material and how it is used are the deciding factors in effective insulation that keeps a home comfortable and pushes energy costs down.

What’s the best R-value for your home? The first thing to find out is the value required for your climate zone. U.S. building codes require a minimum R-value insulation for homes — in most zones, the value for, say, insulative wall sheathing is R-11.

The Oak Ridge National Laboratory Building Envelope and Materials Program offers a very informative Web site with information on all types of home insulation. Its fact sheet on insulation can be found at www.ornl.gov/sci/roofs+walls. Included in the HTML version of this fact sheet is a handy calculator called Zip-Code, which gives the recommended R-value for insulation — and the estimated cost of installation — depending on where you live, what part of the house you need to insulate and what type of heating system you use. Read through the contents to learn about home insulation, the best ways to install it and whether you can install certain types of insulation yourself or should hire a contractor to do the job.

Home Tip: Quality insulation materials have a clearly stated R-value and details on the type of material, how it should be used and safety instructions. Check the labels before purchasing insulation.

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