Air Source Heat Pump Guide

What are air source heat pumps and how do they work?

Air source heat pumps are a completely renewable way of heating your home effectively and efficiently by harvesting heat from the air outside of your home, even in winter.

Air source heat pumps essentially take the heat from the air – even if the temperature outdoors is below freezing and transfers this energy to heat the water for your home.

You will simply need an outdoor unit, which only requires electricity and water connections, this heats the water inside your home, via a hot water tank, giving you an efficient and cost-effective heating solution.

Ecodan air source heat pumps can operate in temperatures as low as -25ºC and are specifically designed to British standards for British homes, you can rest assured your system will continue to perform to a high standard, even in the height of winter. Ecodan heat pumps are manufactured right here in Britain, by the experts here at Mitsubishi Electric.

Residential air source heat pumps aren’t a new development by any means - they have been used in Scandinavian countries for decades. They’ve also been installed in thousands of homes around the UK for a number of years now, so they’re a tried and tested form of efficiently providing heating and hot water for your home.

"You won’t need to worry about your house temperature dropping"

Air source heat pumps are considered completely renewable as the air is naturally heated, which produces the energy the heat pumps utilise. They are powered by an electric supply, and as the UK continues its journey toward net zero, more of the electricity supply will be from renewable sources.

Unlike other intermittent heat sources that provide a sudden release of heat into the property which will be lost once the heating system is turned off, Ecodan air source heat pumps are more efficient when left on, giving you a consistently warm home. This means that in the colder months of the year, you won’t need to worry about your house temperature dropping. You can also simply control your home’s temperature via the app on your smartphone or a traditional thermostat.

What’s more air source heat pumps are compatible with existing transmitters of heat, for example, radiators and underfloor heating, or can be installed as part of a brand-new heating system within your home.

Benefits of an air source heat pump

There are a huge number of benefits to installing air source heat pumps in your property, including:

• Futureproofing your home – There is now a huge push for more renewable heating solutions, so it’s worth getting ahead of the curve by getting your home ready before the inevitable mass market switch.

• Good for the environment – Renewable forms of heating such as air source heat pumps are a far more environmentally friendly alternative to fossil fuels. According to The British Gas Carbon Cruncher Tool, the average three-bedroom property could save 1,404 kilograms (kg) of CO2 every year by simply switching from a gas boiler to a heat pump.

• Government incentives – The government has released several schemes to encourage more people to install renewable heating in their homes. You’ll find the Boiler Upgrade Scheme  and the  Home Energy Scotland Grant & Loan are two great options if you are looking to make the switch to heat pumps. We have a more detailed look at this later in the article.

• Can be used in conjunction with other renewable energy sources – One of the major benefits of air source heat pumps is that they are capable of working alongside other sources of energy, such as solar panels and battery storage. This means that you’re in a position to double up on renewable energy sources, allowing your solar power and/or battery to provide power for your heat pump too.

• Quiet and effective – Not only are air source heat pumps a great source of renewable energy, but they are also extremely quiet. The units operate at around 40-60 decibels, which is essentially a low whirring sound

Government incentives 

To encourage more homeowners to switch to eco-friendly ways of heating their homes, the government has launched several initiatives, based on several factors, to help with the costs associated with installing renewable energy heating sources.

The Boiler Upgrade Scheme opened applications in April 2022 and enables homeowners to switch to more renewable forms of heating systems with financial support from the government. Managed by Ofgem, there is a £450 million pot available to homeowners who can secure the following funding for switching to renewable forms of heating.

You can get one grant per property. Current grants are available for:

• £7,500 towards an air source heat pump
• £7,500 towards a ground source heat pump (including water source heat pumps and those on shared ground loops)
• £5,000 towards a biomass boiler

You cannot get a grant for a hybrid heat pump system (for example a combination of gas boiler and air source heat pump). The system you install must meet certain standards, such as minimum efficiency levels (your installer can advise you on these).

The system’s maximum capacity must be less than 45kWth - anything over is not eligible.

The scheme applies to all homes and non-domestic properties in England and Wales. The main aim of the initiative is in line with government goals to phase out fossil fuel heating to hit net zero targets.

There are various eligibility requirements that need to be met to qualify for the scheme:

• It is only applicable to full heating and domestic hot water systems
• Installers must be MCS certified
• The only systems covered are air source heat pumps, ground source heat pumps, biomass boilers and water source heat pumps

For Scotland, The Home Energy Scotland Grant & Loan covers the following:

• £7,500 - Air source heat pumps (ASHP) & Biomass boilers
• £7,500 - Ground source heat pumps (GSHP) & Water source heat pumps (WSHP)

You can receive a maximum of £15,000. £7,500 as a grant as well as an additional £7,500 interest-free loan. An additional £1,500 is available to homeowners in rural areas.

Loan Repayment Periods:

• 5 years - Anything under £5,000
• 10 years - £5,000 - £9,999
• 12 years - Anything above £10,000

Cost of air source heat pump installation

The cost of installing an air source heat pump does vary based on the size of the system being installed, but data collected by the National Audit Office (NAO Report) found that, in 2023, the average heat pump installation cost was £11,287. That means that on average heat pump owners were paying £3,787 for a new install, after taking the Boiler Upgrade Scheme or The Home Energy Scotland Grant into account.

Further reports published by   (on behalf of UK Gov) give more detail around average cost based on property size, the findings in the report show that a fully installed heat pump requiring upgrades to the radiators are typically in the region shown in the below table.

Table 1 – Typical cost of heat pump installation with radiator upgrades

Typical costs reduce in scenarios were there is no need to upgrade the radiators, as shown in the table below.

Table 2 – Typical cost of heat pump installation without radiator upgrades

Remember both Table 1 and 2 above represent costs without the governments Boiler Upgrade Scheme or The Home Energy Scotland Grant, of £7,500.

To get a better idea of the installation cost for your home, we would recommend calling out a Mitsubishi Electric’s accredited installer, who will be able to assess your property through running a heat loss calculation and recommending the most appropriate heat pump solution for your requirements

Air source heat pump maintenance 

When it comes to maintenance of air source heat pumps, you can rest assured they are generally easy to look after and keep in good condition. On average, each 5-10 kW unit installed costs £300 in maintenance per year according to the report published by Eunomia.

If you want to get the most from your heat pump in terms of overall efficiency, it’s always best to get your system serviced once every year by a professional. We’d recommend using one of the qualified Mitsubishi Electric Accredited Installers, to ensure they have extensive knowledge of your unit. We also offer various service and maintenance plans for our Ecodan air source heat pumps to suit your individual needs.

Mitsubishi Electric also utilise the MELCloud app, which provides remote diagnostics to help identify any problems quickly and easily, all you need to do is sign up to the app and link your unit to the app. Alongside this, there’s an extensive library of troubleshooting tips to help you get your unit running at optimal performance again.

There are also a few steps you can take to keep your unit running as efficiently as possible all year round.

• Keep the unit clean - Regularly cleaning your unit and fans can go a long way to ensuring that the heat pump works as effectively as possible. It can also minimise the risk of damage to the unit. A more in-depth clean will be covered as part of your yearly maintenance, so it’s usually safer to just stick to cleaning around your unit.

• Remove any obstructions – It’s always a good idea to do a regular check around your unit for any obstructions, removing things such as leaves from around your unit will ensure it continues to perform at optimum level all year round.

• If in doubt, call a professional - It can be tempting to try and sort things out yourself if a problem does crop up, but it’s always best to leave it to the professionals. Calling a registered professional will help to diagnose any issues without voiding your warranty too.

Is an air source heat pump right for you?

After seeing the many benefits that heat pumps can bring to your property, you may be wondering if there are any considerations that make these units more suitable to specific properties than others. Here are a few things you need to consider when deciding on if an air source heat pump is right for your home:

• Outdoor Space – With most units coming in at less than 1100mm in height and width and a depth of under 500mm, you don’t need a huge amount of outdoor space to comfortably accommodate an air source heat pump. 

• Is Your Home Insulated? –  we’d recommend that your home is fully insulated as a first port of call, then consider installing an air source heat pump to heat your home.

How can I purchase an air source heat pump? 

Ready to start your journey toward renewable heating? To get started, simply visit our HVAC installer page, where you can easily find an installer in your area.  

If you have any more questions about air source heat pumps, then we’d encourage you to check out our handy heat pump FAQs, which has a wealth of information you may find useful.