You can significantly reduce swimming pool heating costs by installing a solar pool heater. They're cost competitive with both gas and heat pump pool heaters, and they have very low annual operating costs. Actually, solar pool heating is the most cost-effective use of solar energy in many climates.
Most solar pool heating systems include a solar collector (heats the water), a filter (removes debris before goes through the collector), a pump (circulates water through the system), and a flow control valve (diverts pool water through the solar collector). In addition, solar collectors are made out of different materials that are more or less appropriate for different climates and different usage patterns.
Collectors for pool heating normally do not require glazing or insulation since they are operated during warmer times of the year. This allows for a simpler design that is far less expensive than domestic hot water collectors. In fact, many collectors are made of heavy duty plastic which is treated with an ultraviolet light inhibitor to extend the life of the panels. The advantages of plastic collectors are that they weigh less than metal collectors and they are much less expensive.
According to Energy Savers, proper maintenance of your system will keep it running smoothly for 10-20 years, and your collector should require little maintenance if the pool's chemical balance and filtering system are checked regularly.
North Carolina Solar Center