The most cost-effective, energy-saving measure you can take is to insulate your attic, because it's where much of a home's energy is lost. Most older houses were built with little or no insulation. In more moderate climates, the minimum recommended R-value is R-30 for an attic, R-11 for walls, R-19 for raised floors, and R-4.2 for ductwork.
Installing insulation with a higher-than-recommended R-value can reap benefits, but only if your insulation is installed correctly. If there are leaks, compressed areas or weak spots where air can flow, all that work and money can be for nothing.
Thanks to our increased awareness of environmental responsibility, many communities and utility companies now offer free energy audits of your home, so ask if you're eligible. Otherwise, check around doors, windows, floors, and switch plates on exterior walls, where air flow is likely to occur. The easiest way to find seepage is to close off a room, light a stick of incense, and watch which way the air flows. Rattling windows and sooty or dusty spots on sills are also signs that air is flowing.
There are other cheap fixes that keep you from having to hire professionals or rebuild your house. Weatherstripping and craft items are common fixes to air flow under doors, rubber gaskets can seal switch plates against the elements, caulk ($5-$8) can fill gaps, heavy cloth drapes can contain window drafts, and simply closing the flue of the fireplace can stop one of the biggest culprits of invading cold air.
All told, you'll have spent $50 to $350 for materials, which means that if you're like the typical family, you'll have made your money back this year or by next winter. Watch our latest Savings Experiment video for the full scoop on weatherizing your house.