Dear Jim: I want to extend the swimming season several months by heating our pool water, but I don’t want to use so much energy needlessly. Are solar systems effective for pools and what type is best? – Clifford D.

Dear Clifford: Heating the pool water just 10 degrees or so is enough to give your family an extra two or three months of swimming each year. Gas, propane or electric heat pumps are the most common pool heating methods. These work well, but they increase your utility bills substantially and contribute to climate change and energy shortages.

Using solar energy is a better method to heat a pool. In fact, heating swimming pools is the most effective way to use solar energy. Solar pool collectors operate at relatively lower temperatures, as compared with space or domestic water heating, so the designs can be simple and inexpensive without sacrificing efficiency.

Another advantage of using a solar system instead of fossil fuel heating is the solar system also can cool the pool water. This is particularly helpful with an aboveground pool, which can get too warm to be refreshing by midsummer.

By allowing the pool water to circulate through the solar collectors at night, the water can be a couple degrees cooler by morning. There are many types of solar collectors for pool heating. There really is not one best type for every home, climate or budget. They all include some type of temperature controller. This compares the temperatures of the water in the pool with the collector. When the collector is hot enough and the pool water needs heat, the filter water is diverted through the collector.

Many of the solar collectors for pools are made of black semirigid plastic tubes attached to main header pipes at the top and bottom. The cool pool water enters from the lower header pipe, flows up the tubes where it is heated by the sun, and out the top header pipe back to the pool. The solar system manufacturers will help you size the system for your pool.

Installing one of these systems is a fairly simple do-it-yourself job. The collectors are lightweight, but strong, so they are easy to handle even when installing them on a roof. For high wind areas, optional special mounting systems are available. They also can be mounted on the ground, flat on top of a pergola or any sound surface.

Another system uses flexible collectors which are delivered in a roll. These are ideal for mounting on uneven or curved surfaces. Another system uses a large reflective parabolic collector to concentrate the sun’s heat. This works well when there is limited sun exposure area.

Another unique design uses a heat exchanger inside the attic to capture heat from the roof. This also keeps your house cooler. The following companies offer solar pool heating systems: Arco Solar Lasers, (915) 855-2934, www.acrosolarlasers.com; Aquatherm, (800) 535-6307, www.warmwater.com; Fafco, (800) 994-7652, www.fafco.com; Heliocol, (800) 797-6527, www.heliocol.com; and Techno-Solis, (888) 997-6527, www.technosolis.com.

Send inquiries to James Dulley, Bangor Daily News, 6906 Royalgreen Drive, Cincinnati, Ohio 45244 or visit www.dulley.com.