Air Source Heat Pump Guide

Air Source Heat Pump Guide

Air source heat pumps extract renewable heat energy from outside and transfer it inside. They use some electricity to do this but have 300% efficiency – for every unit of energy they use, they produce three units of heat.

This makes them three times more efficient than traditional electric and gas heating systems.

Increased efficiency means a reduced carbon footprint. It also means lower energy bills, saving you up to £1,350¹ on your annual energy costs.

You could receive incentives for using an air source heat pump

It’s a great time to switch to an air source heat pump as there’s currently a government incentive scheme for renewable energy.

You could receive an income of around £1,000 a year for the green energy your pump generates. You can find and more and apply via the Ofgem website.

Air source heat pumps last for many years and don’t need a lot of looking after. Combined with the savings you’ll be making on your energy bills, this makes switching seem like a shrewd choice.

But in case you’ve got any questions or just want to know a bit more, we’ve gathered all the info into one place to give you a comprehensive air source heat pump guide.

What is an air source heat pump?

An air source heat pump is a sustainable way of heating your home. It extracts heat from the outside air and works like a reverse refrigerator to heat water or air.

It can run all year round, even if it’s as cold as -15°C.

An air source heat pump is powered by electricity and is about three times more efficient than a traditional heating system.

This greater efficiency reduces your energy bills, and you can save even more with the government’s Renewable Heat Incentive.

An air source heat pump looks similar to an air conditioning unit and because it’s positioned outdoors, it’s not disruptive to install.

Once you’ve got one, it needs very little maintenance, unlike some conventional heating systems.

Do air source heat pumps save energy, and if so, how?

Air Source Pump Efficiency

Air source heat pumps save energy by working in a more efficient way than other types of heating system. In comparison:

  • Gas central heating is 90% efficient because it makes 0.9 units of heat per unit of gas
  • Electric heating has an efficiency of 100% because it produces one unit of heat per unit of electricity
  • Air source heat pumps are 300% efficient because they can make three units of heat per unit of electricity
  • DATA SOURCE: TheGreenAge

    Go zero-carbon

    Although air source heat pumps need electricity, you can make yours zero-carbon by using a renewable energy source, like solar.

    What are the positives and negatives of an air source heat pump?


  • Easy to install
  • It can heat both the house and your water
  • You get lower energy bills
  • Potential income via the government’s Renewable Heat Incentive
  • Your home produces less carbon emissions
  • Minimal maintenance
  • Lifespan of up to 40 years
  • Cons

  • External space is needed for installation (it’s a similar size to an air conditioning unit)
  • The external unit makes noise and emits cold air
  • It works best in well-insulated homes with large radiators or underfloor heating
  • Costs and savings

    It’s important to think about costs and savings when considering an air source heat pump for your home.

    Let’s take a look at the potential costs and savings as calculated by the Energy Saving Trust.

    Figures are based on an average four-bedroom detached house.


    The cost of buying and installing an air source heat pump ranges between £6,000 and £8,000.

    In most homes with conventional heating systems, an air source heat pump will lower annual energy costs, as detailed below in Savings.


    If you have old:

  • gas central heating, you’ll see savings of up to £465
  • coal heating, you’ll see savings of up to £525
  • oil heating, you’ll see savings of up to £545
  • electric storage heating, you’ll see savings of up to £990
  • Liquid Petroleum Gas heating, you’ll see savings of up to £1,350
  • If you have new:

  • LPG heating, you’ll see savings of up to £450
  • electric storage heating, you’ll see savings of up to £545
  • Additional savings can be made through the government’s Renewable Heat Incentive. This can provide an income of approximately £1,000 a year for seven years, paid quarterly.

    To find out how much you could earn by installing an air source heat pump, try the Renewable Heat Incentive Calculator.

    How do air source heat pumps work?

    Air source heat pumps use a refrigeration system similar to those in fridges and air conditioners.

    They work using a three-stage cycle:

    Air Source Pump Diagram

    Types of air source heat pump

    There are two different types of air source heat pump:


    This type of system feeds heat directly into the home via fans, so it can’t heat your water.

    However, it can be used like an air conditioner, feeding cool air into the home during the summer.

    The government’s Renewable Heat Incentive does not currently apply to air-to-air heat pumps.


    If you want a system for both heating and hot water, you need an air-to-water heat pump.

    This feeds heat into a wet central heating system for distribution around the home.

    You can claim support through the government’s Renewable Heat Incentive if you get an air-to-water heat pump.


    Do I need planning permission?

    In England and Scotland, the installation of one air source heat pump falls under permitted development and does not require planning permission, unless you have a listed property.

    In Wales and Northern Ireland, you’ll need to apply for planning permission from your local authority.

    Regulations are frequently revised, so double check whether you need planning permission when you are ready to go ahead.

    What is the typical warranty period?

    Warranties range from five to 10 years and cover parts and labour. Air source heat pumps can last 40 years, so it’s well worth keeping up with maintenance after the warranty runs out.

    Very little maintenance is required and the manufacturer will advise the recommended intervals.

    Will it need maintenance?

    A small amount of maintenance will be needed and you should check the manufacturer’s instructions for their recommendations.

    You will likely be able to perform basic maintenance yourself, like checking the pressure gauge, changing filters or cleaning parts.

    Additionally, a periodical professional servicing is often recommended. If you opt for an air-to-air heat pump, it’s best to get this done before the start of summer.

    If you go for an air-to-water heat pump, book it in before winter sets in.

    Can I get paid for the heat generated?

    You can receive financial support through the government’s Renewable Heat Incentive if you install an air-to-water heat pump.

    The scheme was set up to encourage people to switch to renewable energy. How much money you get depends on how much energy your air source heat pump generates.

    Payments range from around £800 to £1,300 annually and are paid to you quarterly for a period of seven years.

    You can get an estimation of your payments by using the Renewable Heat Incentive Calculator.

    ¹ The maximum saving of £1,350 can be achieved if you have an old G-rated LPG boiler and live in an average-sized four-bedroom detached house. Visit the Energy Saving Trust website to see the maximum savings possible for all types of heating system.

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