Button Up Drafty Old Homes to Cut Bills

· Seal air leaks: Another priority for both Mertz and Lord is sealing air gaps with caulk or spray foam and weatherstripping doors and windows. Old houses are notoriously leaky, and plugging those gaps is a cost-effective way to bring energy costs down. And there's a bonus for people who cringe at the thought of disturbing an old home's integrity: "It doesn't hurt anything," Mertz said. Lord recommends investing in good weatherstripping, such as spring-action types. But even inexpensive foam weatherstripping works fine, she said. It just won't last as long.

· Address windows: Old, single-pane windows are notorious energy wasters, but original windows are also central to an older home's charm.

Both Mertz and Lord recommend storm windows as an economical way to preserve those old windows and improve their efficiency. Storm windows help block air flow, and the air gap they create has an insulating effect. They prefer exterior storms, because interior ones are prone to condensation that can rot window sills.

Can't afford storms for all your windows right away? Clear plastic window insulation is a cheap, temporary alternative, Lord said. Or take Mertz's suggestion and install insulated thermal window shades.

Lord thinks a major reconstructive effort should be a last resort. But should you decide to replace your windows, Mertz suggests selecting a company that specializes in custom windows. It can match the size, shape and architectural details of the original windows, and it will probably charge less than a company that makes stock windows primarily but also does some custom work, he said.

· Upgrade the heating: Heating systems have come a long way in terms of efficiency. A system installed in the 1950s or '60s is probably 50 to 60 percent efficient, whereas 90 to 95 percent is common today, Mertz said.

"There can be a tremendous amount of saving by just replacing that," he said. Even if you aren't ready to upgrade the whole system, it's wise to install a programmable thermostat, Lord said. It automatically adjusts the heat or air conditioning at night or when the house is empty, making it easy to save heating and cooling dollars.

· Other changes: When it comes time to replace appliances, look for energy-efficient models, Mertz recommended. Refrigerators and clothes washers have made especially big strides in efficiency, but any energy savings add up. If you need to replace a water heater, Lord recommends looking into a tankless model. It heats water on demand rather than holding heated water in a tank until it's needed, resulting in significant energy savings, she said.

Tankless heaters cost up to twice as much as conventional water heaters and must be professionally installed, but you should see a return on your investment in two or three years, she said. What's more, she said they have an average life span of 25 years as opposed to seven to 10 for a tank-style heater. Buy one from an experienced contractor who can calculate the proper size for your household and order a professional-grade model, she recommends.