The top of the range inverter swimming pool heat pumps from Hydropro offer one of the cheapest ways to heat a swimming pool. This inverter range will operate to an outside air temperature of -10 °c and hence can heat swimming pools year-round even during the coldest months of the year. Models in the range start with the Hydropro PX7/32 for smaller size swimming pools. The Hydropro PX11/32 model is one of the best selling in the range being able to heat a pool with up to 55 cubic metres of water volume, features include a digital controller and an automatic defrost facility. The Hydropro inverter heat pump range is unique in the fact that they can also cool swimming pools if required. For larger swimming pools with a pool volume of up to 120 cubic metres we would recommend the PX21/32 model. The larger models in the range are also available as a 3 phase – 400-volt electricity supply option.