The most energy efficient heater Air sourced heat pumps are the most energy efficient and cost-effective method of heating your spa or pool water. When compared to gas or electric heaters, a heat pump uses a tiny portion of energy to generate the same  amount of heat output. By using refrigeration technology a heat pump only requires a small amount of energy to run a fan motor and compressor, and can output over five times more energy in heat compared to what it  consumes in electricity. This means a PowerSmart heat pump will use around 75% less energy than a standard electric spa heater and 55% less energy than natural gas. The massive saving in electricity allows you to cost effectively keep your spa, swim spa or plunge pool at temperature and ready to use all year round, or cost effectively extend the swimming season in your swimming pool.