Well insulated attic space… Photo: umbugjug.com
Contain the Heat
How much insulation does your home need and where? It depends on your climate and the energy costs in your area. The basic principle is that you want to keep heat energy from doing what it does best: dissipating to colder areas. The best way is to trap a layer of air next to the heat source. In new framing, sprayed-on polyurethane foam, fiberglass or cellulose do a good job of providing this layer before the drywall goes up. If you're retrofitting your insulation, you can still spray in cellulose through holes cut from the interior or the exterior.
Choosing the Right Insulation
To find out what insulation will work best in your home, you'll want to know the recommended insulation r-values in your area. R-value is the measure of a material's resistance to heat flow. The higher the value, the more effective it is. To see the recommended insulation r-values and cost estimates in your ZIP code, visit the Department of Energy's Web site.
Even a small draft can make your insulation less effective. Seal any gaps around electrical outlets, ducts, windows and doors with foam sealants, caulking, or weather-stripping.
Focus on the Attic
The most important area to insulate is your attic. Make sure you've got at least the attic floor insulated with blown-in or batt insulation to your area's recommended r-value, and consider insulating the roof and attic walls as well. This can provide a fully insulated buffer zone to keep heat where you want it and keep the lid on your energy costs.