Plugging Those Heat Leaks

Second of a two-part series

Q With heating oil and gas prices skyrocketing, what are some basic steps to take that will return a significant payoff over time?

A Last week, this column discussed quick, low-cost steps that can have a significant payoff, including using an electric space heater to keep one key room comfortably warm while you turn heat in the rest of the house really low. This week, we'll look at longer-term approaches to this issue.

The first step is to figure out what will make a real difference in your particular house. Don't waste your money on more insulation, new windows, a better furnace or any of the other things people may try to sell you until you first hire someone who knows how air flows through buildings and can determine where your house is leaking heat.

This person needs experience and training, plus the right equipment: something called a "blower door" and, if possible, an infrared scanner.

With a blower door, a skilled technician can find out what kind of air leaks your house has. The blower door itself is a large fan that is sealed into the doorway of an open, exterior door. The fan blows air into the house. With all the windows and other exterior doors shut, that increases the air pressure inside, so of course the pressurized air tries to escape. By feeling with a hand or by watching where puffs of smoke trail, the technician can usually pinpoint where this is happening.

Once you know where the gaps are, you can go about plugging them. If there are significant leaks, plugging them is always the first step in making a home more energy-efficient. Ask the person who did the test for advice. Often, the remedies are quite simple. If you find gaps around pipes that extend through your attic, for example, you can probably plug them by filling plastic bags with fiberglass insulation and then stuffing the bags into the holes. (The plastic bags are important because fiberglass has little insulation value unless it is in a sealed cavity.) With an infrared camera, the technician can determine where the exterior of your home is warmest and coldest. Hot areas may show up in red and cold spots in blue, or whatever colors the camera is programmed to spit out. By deciphering the color code, you can determine where insulation is thin or missing. Again, ask the person who did the test for advice about whether the results point to cost-effective improvements you can make.

To find companies that perform blower-door tests and use infrared cameras in this way, go to the Web site run by the Residential Energy Services Network, http://www.natresnet.org/ . The consumer resources section lists certified raters -- people with the knowledge and equipment needed to determine whether homes are energy-efficient. These people all have blower doors and many have infrared cameras. The Residential Energy Services Network, which is associated with the mortgage industry, lists these professionals because some home loans offer special benefits for people who buy energy-efficient homes (based on the concept that these houses should be less of a drain on monthly budgets than ones that cost more to heat). But nothing stops you from tapping into this network for help in determining how to cut your heating bills.

The evaluation may cost you $300 to $500, but it could save you from wasting money on things that might make little difference in your heating bills. Because energy-efficient houses also tend to be most comfortable, think of the evaluation as not only a way eventually to save money but also as a means to improve conditions within your home.

"If you're not feeling well, you go to your general practitioner," says Tom Marston, marketing director of Energy Services Group, a company in Wilmington, Del., that performs blower-door tests and advises customers on energy-saving measures. "That doctor may find a problem with your heart, so he refers you to a specialist. The point is, he leads you down a path that eventually solves your problem." Getting a blower-door test and an infrared scan of your house is a similar process.

While you wait for the tests, you might also dig out a year or two of your past utility bills, especially if your heating costs are hidden within bills for other utilities. Plot the energy you've used so that you can see a grid that shows 12 months at a time. By studying the curves and subtracting the wintertime spike that corresponds with heating costs and the summertime spike from air conditioning, you can determine how big a proportion of the total is spent on lighting and appliances. In your home, these might be the real energy guzzlers. If they are, investing in more insulation or new windows might make less sense than switching to more efficient light bulbs and a better washing machine.