Q. I want to build a conventional-looking house that uses solar heating and cooling without the big solar roof collectors. I would like a spacious open floor plan. What solar features are best? — F.R.

A. What you want to build is called a passive solar house. Passive solar means that there are no solar collectors, pumps, water tanks, etc. The house itself captures and stores the sun’s heat in the winter and naturally stays cool in the summer.

A spacious open floor plan with many windows, lofts, cathedral ceilings, and sunrooms is a natural fit with passive solar heating and cooling. This allows the sun’s warmth to naturally circulate throughout the house.

In most climates, it is possible to build a 100-percent solar house that looks conventional. Several companies now sell do-it-yourself passive solar home kits up to 4,000 square feet in size.

The keys to an effective passive solar house are high insulation, much south-facing glass and thermal mass built into the floors and walls. Having the proper ratio of glass area to thermal mass is important.

In the summer, a passive solar house stays comfortable without air-conditioning. The thermal mass absorbs excess heat in the daytime to keep the house cooler. Building a simple solar ventilation chimney creates a natural breeze throughout the house to cool it all day.

Four basic passive solar design features to use are direct gain windows, solar walls, sunrooms and solar roofs. To attain nearly 100-percent solar, a combination of all these features is needed. You’ll still probably want a fireplace or small space heater for the coldest winter nights.

Direct solar gain with large south-facing windows is most effective. Typically, a thick concrete floor covered with decorative ceramic tile is in front of the window to store the sun’s heat. At night, ceramic tile is effective at slowly reradiating the heat back out into your house.

A solar wall is a masonry or decorative stone wall (for thermal mass) built just inside a large south-facing window. A sunroom is effectively a giant solar collector. Its floors and walls store some of the solar heat for the night. The remainder of the heat circulates throughout the house in the day.

For summer comfort, the house should have large roof overhangs. These are attractive and block the summer sun which is high in the sky. If you want to run a small window air-conditioner, the thermal mass stores the “coolth” and allows you to run it at lower off-peak nighttime electric rates.

Write for Update Bulletin No. 835 listing 14 manufacturers of do-it-yourself passive solar house kits, floor plan layouts of 11 houses utilizing passive solar design features and a thermal mass material selector chart. Please include $2 and business-size SASE. Send to James Dulley, 6906 Royalgreen Drive, Cincinnati, Ohio 45244.

Q. I want to place my new clothes dryer on an inside wall. It would be easiest to vent it upward through the roof. What is the best and most efficient way to vent it? — A.H.

A. You must vent a dryer properly through the roof or it constantly sucks heated air out of your house. Use a special vent cover made just for roof venting. It seals well when the dryer is not running. Twenty feet is about the maximum duct length or the air resistance may become too great.

Insulate the duct in the unheated attic area. Even in a mild climate, the moisture laden air inside the duct can sometimes condense and drip down.