Q - I am interested in using solar cells to produce free and clean electricity for my home. I already use them on my camper. What types of solar cell systems are available for home use? P.K.

A - Electricity-generating solar cells (photovoltaics) produce electricity naturally when the sun shines on a panel of many interconnected solar cells. There is no sound, pollution or waste produced. With no moving parts, a solar cell panel should last a very long time with proper care.Although it is possible to use photovoltaics to provide all the electricity for a house, it is much less expensive to get your electricity from your electric utility company. However, for a remote home or cabin that is a long distance from existing power lines, it may be cheaper to install a photovoltaic system than to extend the electric power lines.

Another application for photovol-taics is to provide light or electricity for operating tools in a backyard work shed. The solar cell panels are connected to batteries that store the charge. The batteries can also be used as an emergency backup system for power outages.

You can buy special tools, refrigerators, lights, that operate on lower-voltage direct current coming from the batteries. By using an inverter and a more powerful solar cell system, you can also operate standard 110-volt alternating current power tools.

Small photovoltaic systems are very effective for campers and boats. These are usually used in the warmer weather when the days are longer and the electricity output is greater. Very small solar cell panels can be used to keep the batteries at peak charge. Larger panels can produce enough electricity to power most of the appliances and lights in a camper.

One large whole-house photovoltaic system provides 4 kilowatt-hours per day. This system could power four 60-watt and two 25-watt light bulbs for four hours per day, a 19-inch color TV and VCR for four hours a day, an automatic clothes washer and gas dryer five loads a week, a microwave oven used 15 minutes per day, a table saw one hour per week, a water pressure booster pump, and an electric lawn mower used one hour per week.

You will still need natural gas or propane for space and hot water heating, and cooking. Electric heat-generating devices would consume too much power for the solar cells to provide. You can also get gas- or propane-powered refrigerators so you can operate more electrical appliances instead.

You can write to me for UTILITY BILLS UPDATE No. 128 showing a list of manufacturers of large photovoltaic solar cell systems and detailed descriptions of eight different size systems from camper-size (100 watt-hours) to whole-house-size (9600 watt-hours) and a chart showing annual number of hours of sunshine for 150 cities. 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 have many houseplants for decoration and to provide humidity in my home in the cooler weather. Will the higher humidity actually help to lower my utility bills? C.D.

A - The theory is that higher humidity levels improve your comfort and reduce cooling moisture evaporation from your skin. This allows you to lower your thermostat in the heating season without being uncomfortable.

It absorbs heat when water evaporates, so unless you set your thermostat lower, it actually wastes energy. Also, houseplants may not be your best source of humidity. Many people are allergic to the mold spores given off by houseplants. When you feel bad, you often set the thermostat higher.