Instead of using large areas of unsightly solar piping or an energy-gobbling electric element, an Alliance Pool Heat pump uses a highly energy-efficient system to heat your pool at minimum cost. As seen in the diagram below, a compressor (1) compresses R410A gas, creating heat which is then transferred to circulating pool water: (2), (3) and (4). Further round the closed circuit, the compressed gas passes through an evaporator (5), becoming extremely cold. A fan (6) blows air at ambient