Dear Jim: I have considered getting a solar water-heater kit to cut my utility bills and protect the environment for my children’s future. How do I know if one will be effective on my house and which type is best? – Megan T.

Dear Megan: Heating your domestic hot water with solar energy can be effective on practically any home. The only requirement is finding a spot in your yard or on the roof that has direct exposure to the sun most of the day. This is not a problem on 95 percent of homes.

The economic payback on installing a solar water-heating kit (some are do-it-yourself installation) depends on your utility rates and the amount of hot water your family uses. As with any product, there are economies of scale so the more hot water you use, the more economical solar energy becomes.

With low interest rates and poor stock market performance, installing a solar water-heating kit can be a good investment. Using solar reduces air pollution, global warming and our dependence on foreign energy supplies. Very little maintenance is required and some kits offer a 12-year warranty.

The new designs of solar collectors are smaller and more efficient. Many are designed to lay flat against your roof so they are barely noticeable from the ground. They are shallow, only a few inches deep, so they resemble a skylight from the ground. They are lightweight, so installation is easy.

There are many types of solar water-heating methods to choose from. The simplest designs and easiest-to-install kits use a thermosiphoning water flow. These are typically mounted on top of your house or garage roof. Thermosiphoning (sometimes called passive) works on the principle that hot water is less dense than cold water, so it naturally rises.

Thermosiphoning keeps water flowing through the solar collector without electric pumps. For this reason, the collector must be mounted higher than the water heater.

Solar water-heater kits with electric pumps offer more flexibility in choosing an effective, sunny location for the collectors. For a totally independent system, choose a 12-volt pump and a small solar cell panel to produce electricity. Mount the solar cell panel next to the collector.

Many solar water-heaters uses a simple flat plate collector design. It is basically an insulated box with a glass top. The water flows through copper pipes that are attached to black solar collector plates inside of the box.

Another unique and effective design uses evacuated double-walled glass tubes instead of heavy insulation. This insulates efficiently and keeps the water hot in the same way a Thermos bottle keeps your coffee hot.

Write for (instantly download – www.dulley.com) Update Bulletin No. 443 – buyer’s guide of 10 easy-to-install solar-water-heater-kit manufacturers, listing collector type and size, features, plumbing layouts, sizing chart and prices. Include $3 and a business-size SASE, and send to James Dulley, 6906 Royalgreen Drive, Cincinnati, OH 45244.