What is a heat pump?



What is a heat pump?


How does a heat pump work?

A heat pump is an alternative to a boiler.  Heat pumps work similarly to a fridge but in reverse. Tens of thousands of heat pumps have already been installed across the UK. They move heat from outdoors into your house and can also remove excess heat from your house to keep it cool. Different heat pumps use different sources of heat.

Heat pumps are a great way to reduce the carbon emissions of your home. They can, in certain circumstances, also help you save money on energy bills. However, it is important to consult one or more certified installers to make sure it is a suitable heating system for your home.

Types of heat pump

  • Air-to-water heat pump

    An air-to-water heat pump transfers heat from the outside air to water. It can then be used to heat your home through radiators or underfloor heating. An air-to-water heat pump can be used to heat your water. This is the most common heat pump in the UK.

    The costs are between £7,000 and £13,000.

  • Ground-to-water heat pump

    A ground-to-water heat pump (or geothermal heat pump) extracts heat from the ground into a fluid, which then heats up your radiators or underfloor heating. This heat pump can also heat your water.

    The costs usually range between £14,000 and £19,000. However, the actual cost will depend on the type of your property and the required groundwork.

  • Air-to-air heat pump

    An air-to-air heat pump is suitable for smaller properties. It uses a fan system for heating and cooling your home. However, air-to-air heat pumps don't heat water.

    The advantages of air-to-air heat pumps are the easy installation and lower costs, which could be between £1,600 and £3,100.

The estimated costs of the different types of heat pump stated in this article were taken from the Energy Saving Trust.

Could a heat pump save me money?

The amount of money you could save from switching to heat pump will depend on several factors, some of which are outlined below. If you would like to know more, the UK Gov website provides a calculator allows homeowners to assess whether a heat pump could be suitable based on details of your home. These include:

  • 1. How well your house is insulated

    Preventing the heat from escaping through your walls, roof and floors will make your home more energy efficient. Heat pumps deliver medium heat continuously. Therefore, your property will need to be well insulated to fully benefit from the heat pump's higher efficiency. Take a look at our guide to insulating your home

  • 2. The climate where you live

    The climate where you live. Heat pumps can extract heat in temperatures as low as -15C. However, the amount of electricity required could increase in lower temperatures as the heat pump would need to work harder. 

  • 3. Your current heating system

    Most heat pumps use radiators and underfloor heating. However, to avoid inefficiencies, you might need to adjust your heating system when installing a heat pump. To work efficiently, heat pumps typically require larger radiators than a gas boiler system.

  • 4. The type of heat pump

    Being highly efficient, heat pumps use less energy than they produce. However, different types of heat pump are suitable for different types of homes and the results will vary - depending on the size of the property, the surroundings and the amount of heat required. Expert system design and installation is essential to ensure maximum efficiency.

  • 5. The cost of electricity compared to gas

    Heat pumps use electricity to operate. Although a well-designed system can provide 3 times more heat energy than the electrical energy it consumes, the cost per unit of electricity used may be up to 4 times higher than the equivalent cost per unit of gas. Heat pumps can therefore cost more to run than gas boilers. This will vary as the prices of electricity and gas change over time. So, it is essential that a heat pump system is well designed for the home to ensure maximum efficiency and lowest running cost. 

Heat pumps V boilers

The suitability of a heat pump or a boiler for your home depends on various factors and will be specific to an individual circumstances. The Energy Savings Trust has provided a range of case studies with personal stories of different homeowners which provide examples of people who have installed Heat Pumps.

Given the complexities involved, if you are considering switching to a heat pump heating system, make sure you consult a certified heat pump installer, e.g. installation engineers registered with the Microgeneration Certification Scheme.

  • Costs and support

    Heat pumps can cost more than a boiler to install. However, to support the government's ambition to install only low carbon heating systems from 2025, financial support is available to partially cover installation costs. This means you could be eligible for financial support to help you switch to a heat pump.

  • Energy efficiency

    Heat pumps are highly efficient as they can generate between 3-4 times more energy than they consume.

    The exact energy savings will depend on your home's current heating system and insulation.

    Ways to improve your insulation

  • Cleaner energy

    Rather than burning fuel, heat pumps use electricity for power and produce much more energy than they consume. Heat pumps can be powered by solar panels or other sources of renewable energy, such as a renewable home energy tariff, which makes them a better option for the planet. The efficient use of energy means that, compared to traditional boilers, much less carbon dioxide (CO2) is produced in the process of heating your home.

Home energy grants and schemes

There are a range of schemes that offer financial support for your energy saving home improvements.

England and Wales

  • The Boiler Upgrade Scheme (BUS) is a scheme offered in England and Wales. Starting in April 2022, BUS will offer a grant up to £6,000 to replace traditional boilers with low-carbon heating alternative. Eligibility criteria regarding current EPC rating and outstanding recommendations for loft or cavity wall insulation apply.
  • If you live in Wales, the Nest scheme also helps with funding energy efficient improvements in low income households. They also offer free and impartial advice on energy and water saving.


  • If you live in Scotland, Home Energy Scotland offers funding and loans supporting energy efficient measures.

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