NFU Energy guide to heat pumps

A heat pump is a device that takes low temperature (low grade heat) and upgrades it to higher temperature (high grade heat). They work essentially by acting like a fridge or freezer but in reverse. With a fridge the inside is cold and the outside is warm, we want the inside of the building to be warm and the outside to be cold. Most heat pumps use a refrigerant which is pumped around a system of pipework from a heat source (air, water, or ground), to the area where heat is required. The low grade heat which is captured, is boosted by a compressor into a higher grade usable heat.