A heat pump is a device which moves heat energy from one place to another and from a lower to a higher temperature.

In heating applications, heat is removed from ambient air, or water, soil or bedrock (from temperatures as low as -18°c) and delivered to where it is needed.

In cooling applications, the reverse happens and heat is removed, to be discharged to the ambient air, water, soil or rock.

Heat pumps use little energy. For every unit of energy purchased as electricity, several units of heat are delivered. So, relating the energy purchased to the energy delivered, heat pumps can be 300% or 400% efficient.