Q. My house is fairly tight and has R-30 insulation in the attic. How much money will I save if I add an additional six inches of insulation in the attic? - P. Rauchet

A. A thorough survey of your house and its heating-cooling system would be needed to even guess at the possible saving from extra insulation. While R-38 is recommended by some experts for attics of new homes in areas where the climate is cool, the investment for retrofitting a house that already has R-30 might not be repaid with fuel savings for many years (the higher the R value, the better the insulation). Incidentally, an additional six inches would bring the attic to about R-49, which is needed only in the nation's coldest areas.

If your heating and cooling bills are reasonable, I'd say that more ceiling insulation would not be a very good investment. If fuel costs are not reasonable, the best bet would be a thorough energy audit to determine exactly where the problem lies.

Q. Our house has light-gray aluminum siding that was repainted dark blue in one area. How can I remove the blue paint? - R. Stipanovic.

A. If you attempted to remove the blue paint by any method, it probably also would remove or mar the underlying gray paint. I think the best bet is to lightly sand the blue-painted area and repaint it with a gray paint that matches the original color. Some paint stores sell special paints for aluminum siding, or you could use any high-grade acrylic-latex house paint.

Q. We recently moved into a house, and every room has a strong, stale odor of cigarette smoke. How can we get rid of it? - J. Strain.

A. If any of the rooms have wall-to-wall carpeting, I'd start by cleaning them thoroughly or having them professionally cleaned to remove clinging odors. Portable air cleaners with charcoal deodorizing filters also should give you some immediate relief. You also should check out the excellent line of odor absorbents and cleaners sold by Nilodor Inc., Box 660, Bolivar, Ohio 44612 (write for information or call 800-443-4321). Most or all of the odor probably can be eliminated in time if the house is kept well-ventilated and you clean or wash surfaces or materials where odors seem to cling.