Saving Energy 101: Insulation

The farther north you go, the more winter is synonymous with cold weather and high heating bills. Homeowners looking to lower their energy bills without sacrificing their comfort might want to consider two significant though oft-overlooked energy saving measures: insulating and air sealing. According to the Environmental Protection Agency’s (EPA) Energy Star program, homeowners who ensure their home is properly air sealed and insulated can save up to 20 percent on their heating and cooling bills.

Here's how it works. When you insulate and air seal your home, you’re preventing the escape of air that’s been conditioned (heated or cooled, depending on the season) by your furnace or AC unit, while simultaneously minimizing the amount of colder or warmer air that can seep indoors. The longer the warm air stays inside, the less hard your furnace has to work (same for cold air and your AC unit), and the lower your energy bills will be.

The vast majority of homes are built with some insulation already installed, but because stringency of residential building codes varies dramatically by state – and because compliance with those building codes is not always very high – even a new home is likely to have less insulation than recommended. In general, homes should have several inches of insulation in their attics, walls and floors in order to maximize efficiency; in fact, most attics should have at least a foot of insulation.

No matter how well insulated your walls are, though, your windows and doors can still be a prime source of air leaks. Sealing these leaks with weather stripping, caulk or spray foam can cut down on energy leaks and make your house less drafty and more comfortable. Weather stripping is cheap and easy to apply, and is also useful for apartment renters, not just homeowners. Additionally, interior or exterior storm windows or shrink-fit plastic sheeting (interior-only) can improve greatly the performance of those windows if they are leaky.

There are many different types of insulation, including fiber glass, cellulose, spray foam and foam board, and the recommended amount of insulation varies by climate. To find out more about how much and which type of insulation is right for you, go to Energy Star’s sealing and insulation page. For more detailed information, check out this Department of Energy Insulation Fact Sheet.