Air to Air Heatpumps push warm or cool air into a room, depending on the desired setting. They are identical to Air Conditioning but instead of only operating in cooling mode, they are able to operate in heating mode too.
Air to Water Heatpumps utilize the same technological principles but instead of directly heating the air in a room, they heat water which can then be pushed through radiators or through hot water systems for washing. Whilst some are also capable of cooling, they tend to do so with less efficacy than Air to Air Heatpumps.