Q - We want to build a house with the lowest utility bills possible, but we want it to look "normal." Is passive solar (no collectors on the roof) a good choice, and what design options do we have? N.T.

A - Designing a house to use solar energy for winter heating and summer cooling is an excellent investment. A passive solar house should cost about the same to build as a conventional house. With a 50 percent to 70 percent reduction on utility bills, it should have higher resale value.Passive solar houses are attractive, open and can be conventional- or unique-looking. Both the large window areas and an interior layout for free flow of warm and cool air contribute to the spacious open feeling.

Basic passive solar options are direct gain, solar walls, greenhouses and solar roofs. You can use one or several of the these in your house. Many super-high-efficiency house manufacturers - dome, modular, log, circular - now offer passive solar build-it-yourself house kits.

Direct solar gain, utilizing large south-facing windows, is most common. The sun shines in on a thick concrete floor, which stores the solar heat. This provides more even heating during the day and comfortable warmth that slowly radiates up from the floor at night. Ceramic tile is an attractive and very effective solar floor covering.

A solar wall is a heavy masonry wall that is built just inside large south-facing windows. As the sun shines on the wall, it stores the heat during the day. At night, the heat is given off into the room.

A solar greenhouse is effectively a giant solar collector. Some of the solar heat is stored in the greenhouse floor and walls. The remainder of the heated air circulates throughout the rest of the house. A solar roof utilizes large windows in the roof and your entire attic becomes a solar collector. You can duct this hot air throughout your entire house.

In the summer, solar energy can be used in several ways to help cool your house. First, design your house with adequate roof overhang. This naturally shades the windows when the sun is higher in the summer sky.

The heavy masonry solar walls or floors tend to moderate and delay the daily summer temperature rise in your house. This allows you to take better advantage of nighttime cooling and lower off-peak electric rates.

For free ventilation, locate a fireplace with a solar masonry chimney on the south or west side of your house. When the summer sun heats the chimney, it creates an upward draft. This draws cooler air in your windows and exhausts the warm air out the chimney using no electricity.

You can write to me for UTILITY BILLS UPDATE No. 284 showing floor plan layouts of six houses utilizing these passive solar options and a list of manufacturers of the passive solar house kits. Write to James Dulley, The Deseret News, 6906 Royal Green Drive, Cincinnati, OH 45244. Please include $1 and a self-addressed STAMPED BUSINESS-SIZE envelope.

Q - I laid rigid foam insulation sheets over the blown-in attic insulation. Since then, the paint on the

ceiling below my attic has been discolored and peeling. Could the insulation have caused this problem? D.S.

A - The sheets of foam insulation board are most likely the cause of the problem. This type of insulation is often a closed-cell material that traps the moisture in the old insulation below it. Before you remove the foam insulation board, first try separating the pieces, leaving large gaps in between them or break them up. This may allow enough area for the moisture to escape through the old blown-in insulation below it.