How do air source heat pumps work?

Air source heat pumps work in a similar way to a fridge, but in reverse - instead of burning fuel to create heat, they absorb heat from the air outside, and use this to heat your home. 

By compressing a refridgerant, air source heat pumps generate heat which can be circulated to your heating system.

There are two main types of air source heat pumps; air-to-water and air-to-air. The difference lies in what form the heat takes when passed to your home.

Air-to-water heat pumps warm your wet central heating system. They need a larger surface area to release heat into your home (like a big radiator or underfloor heating), and the hot water can also be stored in a cylinder for hot showers, baths and taps. Air-to-water heat pumps are more straightforward to integrate into your existing central heating system, and are the most common type of heat pump in the UK.

Air-to-air heat pumps use fans to circulate warm air around your home, instead of radiators. In summer, you can run an air-to-air heat pump to cool your home, too! However, air-to-air systems cannot product hot water, so you'll need a second immersion heater or similar water heating system as well.

Air source heat pumps use electricity to run, but since this is less electrical energy than the heat that it produces, they are an energy-efficient way to heat your home. 

Visually, an air source heat pump looks similar to an air conditioning unit, and are installed on an outside wall of your property. You'll also have a hot water cylinder inside your home.