Air-to-water heat pump: heating, hot water and cooling options

An air-to-water heat pump takes heat from outdoor air and transfers it to the home's water-based heating system. A correctly specified solution can heat rooms and provide domestic hot water. This differs from an air-to-air unit, which normally transfers heat directly to indoor air. ^S10

The choice depends on more than the capacity printed on the unit. You need to know how much heat the home needs in the coldest design conditions and the water temperature required by the floors or radiators. Manufacturer figures must be compared under the same conditions. ^S11

Some units can also cool, but this function depends on the model, controls and indoor system. Not only the heat pump but also the pipework, heat emitters and condensation control must suit cooling. A feature listed in a catalogue is not a complete cooling system.

Before ordering: provide information about the building, existing heating and hot water use. Also show the possible outdoor unit location. Choose the final option based on the whole system's operation, not just the lowest equipment price.