AquaComfort PT-125 PureTemp Heat Pump 118K BTU - Heat pumps capture free heat in the air and transfer it to your pool water, making it one of the most energy efficient ways to heat your pool or spa. Compared to gas, oil, or electric heaters, this heat pump uses just a fraction of the energy to generate the same amount of heat. In fact, heat pumps can be over 5X more efficient than other heating methods. That means you have more comfortable water and a longer swim season for you and your family.