Heat pump cooling vs air conditioning

They are closely related technologies

A reversible heat pump and an air conditioner work on the same principle: a refrigerant cycle that moves heat from one place to another. An air conditioner moves heat out of your home; a reversible heat pump can move heat in or out, depending on the season.

In other words, a reversible heat pump already contains the machinery to cool. The question is usually whether to use it for cooling, or to add a second, dedicated system.

Cooling with a heat pump you already have

If you have a Vaillant aroTHERM Plus supplied without cooling, cooling can be unlocked by fitting the Vaillant cooling plug and having an installer enable the function. There is no second outdoor unit and no second machine to maintain.

The main consideration is how the cooling is delivered indoors. Heat pump cooling circulates chilled water, which works well through fan coil units, and less well through ordinary radiators. The system also needs dew-point control to manage condensation — confirm what your setup needs with an installer.

Installing a separate AC system

A standalone air-conditioning system — for example, wall-mounted indoor units fed by their own outdoor unit — is a self-contained way to cool. It is independent of your heating, can be sized purely for cooling, and is a familiar product for installers.

The trade-off is a second system: another outdoor unit, separate pipework, separate maintenance, and additional cost, alongside a heat pump that may already be capable of cooling.

Frequently asked questions