Dear Jim: I want to install a solar water heater kit on my roof, but I am not sure if it is a worthwhile investment or if it will look bad. What options do I have and can I install any of them myself? – Paul M.

Dear Paul: Installing a solar water heater system will definitely reduce your monthly utility bills. The amount of savings depends upon many factors such as your local climate, utility rates, orientation/exposure to the sun and your family’s hot water usage patterns.

You should plan on spending several thousand dollars to install a reasonable-size solar water heater. If you now have a gas water heater in good condition, it will take many years for a solar system to payback its cost. Electric water heaters are much more expensive to operate, so the payback will be faster.

The hot water output from solar water heaters is often specified by the manufacturers, so the dealers can help you determine the payback. All solar dealers I have known have been honest about the hot water output, so take their advice. They are usually small companies that rely on word of mouth for new business. They definitely do not want dissatisfied customers.

There are other non-financial factors to consider as well. A good-quality solar system will produce free hot water for a long time and will not create pollution or gases that contribute to global warming. This will allow clean fuels, such as natural gas, to be used for other critical purposes and will extend their supply.

The two basic types of solar water heaters are ones that use pumps and thermosiphoning (no pump) models. Thermosiphoning models are the least expensive. These rely on the fact that hot water is less dense than cold water to create the water flow through the system. With a thermosiphoning system, the water storage tank is located above the solar collector.

A pump-type solar system typically uses an insulated water tank in the utility room or basement or just a heat exchanger coil in a water heater. Temperature sensors in the solar collector and the water tank determine when the water circulation pump should run. In cold climates, these systems have freeze protection.

Flat-plate collectors are the oldest technology, but are still effective. Evacuated-tube designs are a newer technology. The sun shines through the glass tube onto the water and the vacuum around it reduces the heat losses.

If you are concerned about how one will look on your roof, consider mounting the collector in a sunny location on the ground. This also makes it easier to clean. Another option is to mount one vertically against a house wall. You may be able to install a no-pump system yourself, but have a pump-type system professionally installed.

The following companies offer solar water heaters: ACRT Solar Roofs, (888) 801-9060, www.solarroofs.com; American Energy Technologies, (800) 874-2190, www.aetsolar.com; Earth Sun Energy Systems, (888) 216-0794, www.earthsunenergy.com; Sun Utility Network, (323) 478-0866, www.sunutility.com; and Thermomax USA, (410) 997-0778, www.thermotechs.com.

Send inquiries to James Dulley, 6906 Royalgreen Drive, Cincinnati, OH 45244 or visit www.dulley.com.