Heating and cooling

Last reviewed: October 2009

Annual savings $550

Approximately 40 percent of residential energy bills are for heating and cooling. That's also where you can reap the greatest savings. In the winter, warm air inside your home rises and escapes into the attic through holes and gaps. It's replaced by colder exterior air that's pulled in through cracks and gaps in the lower levels. That leads to drafty, uncomfortable rooms and high energy bills, even in newer homes. "There's a huge gap between what's in the building code and what's needed for optimal energy efficiency," says Frank O'Brien-Bernini, chief sustainability officer for Owens Corning, an insulation manufacturer.

Eliminate leaks

Use a combination of caulk, foam board, expandable sealant, and weather stripping to fill gaps. Attics in particular are often full of holes from recessed lights, electrical wiring, chimney chases, and more. Look for dirty insulation, which is a sign of air leaks. In the basement, check for gaps around ductwork and plumbing pipes. And don't forget about window and door frames, as well as electrical outlets and switches. Cracked caulking and staining around those openings are indications of air leaks. One trick of the trade: Turn on all of the exhaust fans in the home and then use an incense stick or smoke pen to spot leaks. Or try that without the fans on a windy day.

Check insulation levels

If your attic has less than 11 inches of fiberglass or rock wool or 8 inches of cellulose, you would probably benefit by adding more. Also check for missing insulation, over the attic hatch, for example. Compressed insulation loses its effectiveness, so don't store things on top of it. You may also need to add insulation in the basement or crawl space. Go to www.energysavers.gov and search for "ZIP code insulation program" to find specific recommendations for your area.

Correct ductwork

It's the last step, and the one that's the most overlooked. Spending $500 to seal leaky or poorly insulated ducts that run through crawl spaces, attics, or other unconditioned areas can save you about $400 per year, according to the Energy Efficient Rehab Advisor, an online calculator available at www.rehabadvisor.pathnet.org. Remediation is dirty work that requires the right materials. Leave it to a qualified heating and cooling pro.

A buttoned-up house won't leak energy, but you should still have your heating and cooling equipment inspected annually, and change furnace and A/C filters monthly. A programmable thermostat is also worth every penny. By automatically lowering your heating-system thermostat 5 to 10 degrees at night and during the day if no one is home, the device will shave up to 20 percent off of your heating costs. It can also save on cooling costs. In our survey, roughly six in ten respondents with a programmable model have seen savings. But you need to stick to those settings to save.

Easy, low-cost solutions

Lock double-hung windows to prevent air from escaping. Open curtains on south-facing windows on cold days to let in the sun.

Energy all-stars

Lux Smart Temp Touch Screen TX9000TS programmable thermostat

The Lux Smart Temp Touch Screen TX9000TS programmable thermostat, $80, was especially easy to operate and maintains steady temperatures. The screen on the $55 Hunter Set & Save 44360 was easier to read than most. Some tested thermostats were so difficult to use that you might end up using more energy.