Why do you have a swimming pool? Relaxation, excersize, social gathering? What ever the reason, a solar pool heater will increase the time you can enjoy your pool by 4 months out of the year. It won't cost a fortune in propane or electricity. These systems can pay for themselves in 3 years! The system uses the pumps already in place, with a simple controller and valve. When the pool needs heat, the valve opens, sending the pool water through the collectors. When it doesn't, the valve closes and the water goes directly through the filter and back to the pool.