What is a heat pump?
A heat pump uses electricity to move heat between places for heating or cooling.
How it works and where it is used
Like a refrigerator, it can use a refrigerant cycle. Air-source and ground-source designs have different installation costs and performance. Moving rather than generating heat can deliver more heating effect per unit of electricity under suitable conditions; actual efficiency depends on outdoor temperature, insulation and design.
Limits, safety and selection criteria
Size the equipment for building heat loss; poor sizing harms comfort and consumption. Filters and systems need maintenance. Refrigerant leaks and electrical work require qualified people. Compare upfront cost, energy tariffs and existing heating infrastructure. An insulated home with low-temperature underfloor heating may suit a heat pump, while older high-temperature radiators need more careful design. Outdoor units can enter defrost cycles in cold weather; this may be normal. Models vary across climates. Noise and outdoor-unit placement also matter to neighbors. Compare heat loss and long-term energy use instead of judging from one bill. Good controls and commissioning are as important as the nameplate efficiency of the equipment.