ENERGY Experts debunk heating myths

Experts say closing registers in some rooms or a basement isn't always a good idea.
KNIGHT RIDDER NEWSPAPERS
Think you're using your heating system to its maximum effectiveness? Maybe so, maybe not.
Misconceptions are common, but they could cost you in terms of warmth, energy spending and even safety. Check out the following myths and see how your knowledge measures up.
Myth: If you close the registers to rooms that are rarely used, the rest of the house will be warmer.
Fact: That's true to some extent, but not if you have a lot of unused rooms, said Gary Jackson, general manager of Jackson Comfort Systems in Northfield, Ohio. A forced-air system isn't a one-way street; air needs to flow through the house so that it can return to the furnace to be reheated. Closing too many registers interferes with that air flow, which results in less heat and less even distribution, Jackson said.
If you have a heat pump, leave the registers open, he said. Closing them could harm it.
Myth: Opening heating registers in an unused basement is a waste of energy.
Fact: Opening the basement registers not only helps your home's heating system work more effectively, but it also helps prevent mold and mildew growth, said home inspector Ezra Malernee of Canton, Ohio. The warm air helps prevent condensation in the basement, which can cause mold. When that heated air rises, it makes the first floor warmer.
Chimney inspections
Myth: You don't need a chimney inspection if you don't have a fireplace.
Fact: If you have a gas-burning appliance such as a furnace or hot water heater, the chimney or flue needs to be inspected regularly to make sure it's sound and clear of nests and other blockages, the U.S. Consumer Product Safety Commission says. Don't assume a heating contractor will check the entire venting system as part of a routine inspection of your home heating system.
Myth: It's pointless to turn down the thermostat at night, because the furnace has to burn so much energy to reheat the house that it cancels out any saving.
Fact: The amount of fuel a furnace uses to reheat a building is roughly equal to the fuel saved as the temperature drops, according to the U.S. Department of Energy. You save energy between the time the temperature stabilizes at the lower level and the time the temperature is raised again. The longer the house remains at the lower temperature, the bigger the saving.
Myth: Duct tape is good for sealing leaky heating ducts.
Fact: Oddly enough, this might be the one job that most household duct tape isn't good for. The adhesive used on most duct tape dries out over time, making the tape ineffective against leaks.
Heating contractors use a special mastic to seal little holes and leaks in forced-air heating ducts that run through unheated areas, but do-it-yourselfers can use caulk, Jackson said. If you do use duct tape, be sure to choose a type with the Underwriters Laboratories seal. The seal indicates the tape will hold up better.