The Solar Pool Heater helps you heat your pool water using solar energy. Pool water is fed from the pump to the pool heater where the water is warmed as it circulates through the heater by the sun's energy and is then returned to the pool. This unit will raise your pool by 10 degrees within 7 days. It can be used for both above ground and most inground pools. Multiple heater units can be connected in a series to increase heating efficiency.