QWe owned a gas furnace for many years and saved on our fuel bills by using an automatic electronic thermostat to cut back on heat by setting back the heating temperature at night and while we were out of the house. Now, we are moving into a new house with two electric heat pumps for heating and cooling. We'd like to use setbacks in the new house to save money, but were told not to. Is it really a bad idea? -- C. Callahan

AYou were given good advice. Setting the thermostat back by several degrees at night in winter and during absences is an excellent money-saving technique with many central heaters, but some electric heat pumps are exceptions. Unless these pumps are equipped with special programmable thermostats designed for heat pumps, you should not attempt temperature setbacks.

Typically, the thermostat for an electric heat pump should be set at 68 degrees in winter, or a few degrees higher if more heat is wanted, and left there. If the house cools because of a thermostat setback, the heater's backup mode, which uses expensive resistance heat (similar to a small electric heater with "hot wires"), will kick in to raise the temperature again. Instead of saving money, it will increase your electricity cost.

Special programmable thermostats for heat pumps, which permit setbacks, have a recovery, or "ramping," feature that gradually brings the temperature back up from a setback. This reduces the use of backup resistance heat and cuts costs.

If you want to use setbacks, the best bet is to consult a heating technician familiar with heat pumps and have the special thermostats installed.

In addition, if you do not have an owner's manual for the pumps, you should try to get one from the manufacturer or installer. The manual should give other tips for the most efficient operation and maintenance of the pumps.

I live in a one-story house with attached garage and porch. I found that the builder did not insulate the portion of the attic over the garage and porch. Will it keep the house warm if I insulate those parts of the attic? -- A. Hartje

Insulation is designed to keep heat from moving to one space or object from another space or object; it doesn't have any heating ability of its own. All heated (or artificially cooled) spaces should be well-insulated on top, sides and bottom. But unless the garage and porch are heated, the main effect of insulating the attic over them would be to help keep them somewhat cooler in summer by helping to block the sun's heat.

The builder appears to have believed that the cost of the insulation over these unheated spaces outweighed the benefits. In short, insulating those spaces will not keep your house warm.

We live in a one-story house with a warm-air furnace in the attic. The house is built on a crawl space that is well-insulated. The heating registers are in the ceilings. Because of the location of the registers, the rooms seldom get comfortably warm from the waist down. Can you offer any solutions? -- H. Young

You might try a ceiling fan in one of the rooms to recirculate some of the warm upper-level air down to the floor level. If it works, you can add fans in other rooms.

If you try this, be sure to get a reversible fan and try it in both modes -- running clockwise and counterclockwise -- to see which works best. Also get a fan with several speeds. A slow speed will probably work best for this purpose.

A ceiling fan will also prove useful in summer, so it could be a good investment in any case.

We have a fireplace that is seldom used except for burning decorative candles. The problem is the draft coming from the fireplace. I stuff plastic bags filled with newspaper into the opening except when I am burning candles. Is there a better, safer way? -- L. Dechant

It sounds as if the fireplace does not have a damper, which could be kept closed to prevent the draft and the loss of heat up the chimney. If you want to use the fireplace, a chimney-top damper is probably the simplest solution.

A damper of this type is opened and closed by pulling a chain that extends down the chimney. A source of dampers and more information is Duke Chimney Services (888-769-9690 or www.dukefire.com).

Prices for top-mounted dampers start around $280. Top-mounted dampers should not be used with vented gas logs or with wood or gas stoves.

Readers' questions and comments are welcome and should be sent to Gene Austin, the Philadelphia Inquirer, Box 861, Blue Bell, Pa. 19422. Send e-mail to austfixit@aol.com. Questions cannot be answered personally.