Do It Yourself: Sealing gaps can solve efficiency at low cost

Q. Our house is about 50 years old and not very energy efficient. We’d like to lower the cost of heating and air-conditioning, but can’t afford big-ticket improvements. Are there any low-cost ways to save energy and improve comfort?

A. One way to save energy is to seal air gaps that allow heat loss and air infiltration. Sealing gaps uses relatively inexpensive materials, such as weather stripping, caulking compound and possibly some insulation.

If you do the work yourself, it is unlikely you’ll be able to seal more than a fraction of the air gaps in your house. More intensive gap sealing requires special equipment like a blower door, which reduces pressure inside the building, causing outside air to rush through gaps and making detection much easier. Tools like this are usually employed in a professional energy audit, which can cost several hundred dollars.

But do-it-yourselfers using more low-tech methods can definitely fix many gaps. The likeliest places to find air gaps is around doors and windows, any pipe or wiring that penetrates the building outer shell, the rim joists or sill plates that are attached to the top of foundations in wood-framed houses, and anything that penetrates ceilings, such as fans, recessed lights, ducts, attic access doors and folding stairs. Other gap sources include electrical outlets and switch boxes on outside walls, siding-foundation joints and siding-chimney joints.

Your first step should be to locate the leaks you want to fix. Some are obvious – you can feel a draft around a window or see a crack of light around a door when it is closed on a bright day. Others are more difficult to find and require some snooping and common sense.

If you want to get more sophisticated, you can buy a thermal leak detector made by Black & Decker for about $25; it’s a hand-held gadget that reveals leaks by noting temperature changes. The tool is available at some home centers and on the Internet.

When you have found the gaps you want to seal, visit a well-stocked home center or hardware store and buy the materials to fix them. You can also check out a variety of weather-stripping types at www.frostking.com. One of the least expensive and easiest to use is V-Seal, which works on windows and doors.

For caulking, most do-it-yourselfers prefer acrylic-latex caulks, which can be used indoors and out and clean up with water. Small packages of fiberglass insulation are sold at some home centers and can be used to stuff larger gaps. Foam insulations in aerosol cans, such as Great Stuff, can also fill larger holes and gaps.

Q. Can you identify electrical generators selling for $500 or less that I can buy at my local home centers and that will operate a sump pump and refrigerator?

A. I can’t tell you what might be available at your local home centers, but there are small, gasoline-powered, portable electric generators in that price range that can power a sump pump and refrigerator -– and often a few other small-wattage devices. Look for a generator that produces at least 3,000 watts.

According to a wattage chart at www.northerntool.com, a one-third horsepower sump pump typically needs 800 watts and a refrigerator-freezer 700 watts. These are “running watts,” or the power needed to keep the appliances running once they have started. The generator should have additional “surge watts,” to start up the devices.

If you can’t find what you want locally, search the Internet with the words Portable Generators for Under $500. If you want a top brand like Generac or Troy-Bilt, you might have to pay a few hundred dollars more but you’ll get more power and features.