Closing off drafts and boosting insulation can help reduce your heating and cooling bills by up to 20 percent, according to Energy Star, a joint project of the EPA and the U.S. Department of Energy. To start, buy simple caulk and weather-strip and plug every known draft site in your house, from the windows and doors to the electric and cable sockets. Then upgrade your home's insulation. A 2003 study conducted by Harvard's School of Public Health estimates that nearly two-thirds of U.S. homes are underinsulated. While seven inches of attic insulation is common, adding another five to eight inches will boost your energy efficiency.
If you're game, tackle the project yourself: To download a free brochure on do-it-yourself insulating projects, go to Energystar.gov and type "home sealing" in the search box. Also, ask a home-supply-store representative about eco-friendly insulation products such as cellulose (shredded, treated old newspapers) and the new generation of formaldehyde-free fiberglass insulation.