Air Filters: Spend: About $30 a year. Annual savings: Up to $100. That's if you change air filters in your heating/cooling system every three months. Choose a pleated model-it'll do a better job.

Programmable thermostat: Spend: About $100. Annual savings: $100. Models like the Honeywell Seven-Day Universal Thermostat ($100) take the chill out of lowering the temp: Your house will automatically be cool when you're out or asleep, warm when you're around and conscious, (and vice versa in the summer).

Water heater blanket: Spend: About $20. Annual savings: $34 a year for a gas heater; $54 for an electric one. Water heaters made 10 years ago aren't well insulated. If yours dates to 1997 or before, it can lose about 3°F of heat an hour. Wrap it in the insulating Thermwell Water Heater Blanket, ($20), and it won't have to work so hard to keep warm.

 

Smart Power Strip: Spend: About $30. Annual savings: $30 per strip. Most electrical devices gobble energy even when they're shut off. Unplugging them is a hassle-so get the Smart Strip ($30; amazon.com). Plug in your printer, speakers and other peripherals and they'll get power only when your computer is on. Same goes for TV and stereo equipment.

 

Compact Fluorescent Bulbs: Spend: About $5 each. Annual savings: About $5 each. The biggest problem with fluorescents is that their bluish light can make even the healthiest homeowner look ready for his last rites. To minimize the operating room glare buy only name-brand bulbs that are labeled "soft" or "warm" light.