What is R-Value and What Do You Need to Know About it

What is R-Value?

As the weather changes and thermostats are set up or down, the R-value of your home’s shell plays a critical role in keeping you comfortable. If you walk through the aisles of a home center, you see rolls and boards of insulation labeled R-1 all the way up to R-38. But what is R-Value?  It refers to the resistance (that’s what the R stands for) of heat-transfer from hot air to cold air. In the cold winter months, a high R-value in your walls will keep your cozy warm air inside. The opposite is true for summer months, when your walls should keep the hot air from creeping into the cool comfort inside. The higher the R-value, the more resistant your home’s shell will be to this transfer.

Comparing R-values

Shopping around for the right insulation for your project can sometimes be confusing. R-value varies by the material, and thicker insulation doesn’t necessarily mean it is better. A rigid-foam board won’t need to be as thick as fiberglass batting to achieve a similar R-Value. Another factor that makes figuring out R-value confusing is that for some kinds of insulation, R-value is measured by the inch. Such types include spray foam and blown-in insulation, which can be applied as thin or thick as the cavity you’re putting it in allows. Here’s the difference between pink, yellow and green insulation.

R-Value not only in insulation

Insulation is not the only factor that contributes to the R-value of your home’s shell. It is definitely the biggest factor, but things like gypsum board, siding, sheathing and even empty air-space provides some R-value, as well.

Knowing what is R-value is an important step in keeping your home comfortable all year round. Check with your local municipality to find out what minimum R-values it recommends in attics, walls and floors in your area.

Originally Published on The Family Handyman