Q - I am considering putting new maintenance-free siding on my house. Will vinyl siding add much insulation value to my walls, and what is the best type to select? R.H.

A - The vinyl siding itself won't add much actual insulation value, but it still may reduce your utility bills. With a good installation job, vinyl siding can reduce the amount of outdoor air that leaks into your house through the walls.You can easily add additional insulation by first placing rigid foam board insulation, like polystyrene foam, over your present siding. The new vinyl siding is nailed over the foam board insulation. Insulation on the exterior wall surface is the most energy-efficient location for it.

Vinyl siding is an excellent choice for most houses and is capturing an increasing share of the replacement siding market. With the new grained surfaces, it is often difficult to distinguish from wood siding, except that you won't have to paint it every several years.

Select a good grade of vinyl siding. Generally the thicker, the better. Material thicknesses of .040 inches or more are good. The thicker material minimizes problems from high summer heat and extremely low winter temperatures. Many good-quality vinyl siding manufacturers offer a 50-year transferable warranty, so the resale value of your house will increase.

You generally should not try to do the job yourself. Since vinyl expands and contracts with temperature changes, it must be sized and hung properly. It is designed with elongated nail holes so it actually "floats" on the nails. If you nailed it too tight, you could have problems.

Each panel usually has interlocking edges. These edges lock and seal tightly over the siding strips above it and below it. Since vinyl blocks water vapor, there are small weep holes in the bottom of the siding strips to let moisture escape.

You should select a siding profile (width of clapboard slat) that is attractive and consistent with the style of your house and area. Profiles range from a width of 3 to 8 inches. The profile width does not have a significant effect on the energy efficiency.

Although hard rains keep the siding fairly clean, you can wash it with a car-washing brush attached to a hose. Since the color goes completely through the vinyl material, small scratches are not very apparent.

You can write to me for UTILITY BILLS UPDATE No. 369 showing a vinyl siding buyer's guide for 20 manufacturers listing surface textures, profiles, and numbers of colors. Write to James Dulley, The Deseret News, 6906 Royal Green Dr., Cincinnati, OH 45244. Please include $1 and a self-addressed envelope.

Q - I try to save electricity and light only as many lights as I need.

They seem bright enough to me, but when my parents visit, they say they are too dim. How many lights should I have on at night? T.O.

A - Both you and your parents may be correct, so use enough lights for comfortable brightness for the activity you are doing. As people age, they often require brighter light and more contrast. Those 30 to 40 years old need an average of 17 percent more contrast than those 20 to 30 years old. Those 60 to 70 years old need 250 percent more contrast.

Each time you double the wattage of the bulbs, you use double the amount of electricity. Try using three-way bulbs in the rooms that your parents generally occupy so you can easily adjust the light intensity.