Moov MR550 Reversible Variable Speed Heat Pump 55K BTU - This heat pump runs on a world-renowned single-speed compressor. Its mission is to heat your pool as much as the weather conditions permit, while offering an impressive level of silence and unrivaled value for your money! In northern climates where temperatures can reach 10 degrees Celsius at the beginning and end of the season, a heat pump with reversible defrosting is imperative.