Choosing a heat pump

Selecting the right heat pump is a critical decision that depends on your property type, available outdoor space, and your budget for upfront installation.

Comparison of heat pump types

Air source heat pumps (ASHP)

The most popular choice for UK homes. The unit sits outside and looks similar to an air conditioning unit.

  • Best for: Most homes, including semi-detached and terraced houses.
  • Pros: Cheaper to install, requires less space, minimal disruption to gardens.
  • Cons: Efficiency drops slightly when it is very cold outside (though they still work well below freezing).

Ground source heat pumps (GSHP)

These systems extract heat from the ground using pipes buried either in horizontal trenches or deep vertical boreholes.

  • Best for: Homes with large gardens or projects where maximum efficiency is the priority.
  • Pros: Most efficient type, extremely consistent performance year-round.
  • Cons: Very high installation cost, requires significant excavation or drilling.

Hybrid heat pumps

A system that combines a heat pump with a traditional gas or oil boiler. The system automatically chooses the most efficient source based on the outside temperature.

  • Best for: Large or old properties where insulation cannot be easily improved.
  • Pros: Provides a “safety net” for very cold days, works with existing smaller radiators.
  • Cons: You still need a fossil fuel supply and pay two standing charges.

Key considerations for your home

1. Outdoor space

Air source units need about 1-2 metres of clearance for airflow. Ground source systems need either a large area for trenches (about 2-3 times the floor area of your house) or access for a drilling rig for boreholes.

2. Insulation levels

Heat pumps work best when they can run at a low, steady temperature. If your home is poorly insulated, the heat will escape too quickly, forcing the heat pump to work harder and increasing your bills.

3. Your current heating system

Standard radiators may need to be replaced with larger “low-temperature” versions to provide enough heat when the water is running at 45°C instead of the 70°C used by gas boilers.

Recommendation: If you have a standard garden and a relatively modern home, an Air Source Heat Pump is usually the most cost-effective and practical choice.