The single most important thing to know about air source heat pump maintenance in the UK
Regular maintenance is essential for keeping your heat pump efficient, but the specific legal requirements and manufacturer warranties differ from those for a gas boiler. Unlike gas boilers, there is no legal requirement in the UK for an annual safety inspection of an air source heat pump. The primary driver for maintenance is to protect your manufacturer’s warranty, which typically requires an annual service by an MCS-certified installer.
Neglecting maintenance can lead to a gradual drop in efficiency (Coefficient of Performance, or CoP) and, in severe cases, compressor failure, which is expensive to replace. The CoP measures how many units of heat the pump produces for each unit of electricity it uses. A well-maintained heat pump might have a CoP of 3.0, meaning it produces three units of heat for every one unit of electricity.
Who is eligible for the Boiler Upgrade Scheme (BUS) grant for an air source heat pump
The Boiler Upgrade Scheme (BUS) provides a £7,500 grant towards the cost of installing an air source heat pump in England and Wales (GOV.UK, 2026). Eligibility requires that you own the property (or have permission from the freeholder) and that the property has a valid Energy Performance Certificate (EPC) with no outstanding recommendations for loft or cavity wall insulation.
The grant is only available for installations completed by an MCS-certified installer. You cannot claim the grant for a heat pump that replaces an existing heat pump. It must replace a fossil fuel heating system such as gas, oil, LPG, or electric heating (Ofgem, 2026). If you are eligible, the grant is deducted from the installation cost by the installer, so you do not need to claim it separately.
Quick numbers, air source heat pump maintenance costs
| Item | Typical figure | Source |
|---|---|---|
| Annual service cost | £150–£250 | Energy Saving Trust, 2026 |
| Typical service interval | 1 year | MCS standards, 2026 |
| Warranty requirement (years) | 7–10 years (varies by manufacturer) | Manufacturer warranty documents |
| Efficiency drop if unserviced | Up to 10% | Energy Saving Trust, 2026 |
The direct answer to "air source heat pump maintenance uk"
For most homeowners in the UK, maintenance is not a legal requirement, but it is a warranty requirement. You must use an MCS-certified installer to perform the annual service to keep your manufacturer’s warranty valid. The service typically includes checking refrigerant pressure, cleaning the outdoor coil, inspecting the fan and compressor, and verifying the system’s electrical connections.
If you install the heat pump yourself or use a non-MCS installer, the manufacturer’s warranty is likely voided (MCS, 2026). Some manufacturers, such as Daikin and Mitsubishi Electric, specify that only MCS-certified engineers can carry out warranty-preserving services. You should check your specific warranty terms, but the standard across the industry is an annual service by a certified professional.
How to choose a heat pump installer
How to verify an MCS-certified installer for your air source heat pump service
Only MCS-certified installers can carry out a service that keeps your manufacturer’s warranty intact. You can check an installer’s MCS certification on the MCS register website (mcsregister.org.uk) by entering their company name or certificate number (MCS register, 2026). Installers must also be registered with TrustMark, the government-endorsed quality scheme for home improvements.
For electrical work, the installer should be registered with a Competent Person Scheme such as NICEIC or NAPIT (TrustMark, 2026). You can ask the installer for their certificate numbers for all three schemes before booking a service. If an installer cannot provide these, they are unlikely to be MCS-certified, and using them could void your warranty.
What happens if you do not service your air source heat pump
Unserviced heat pumps can experience a gradual reduction in efficiency, leading to higher electricity bills. The most common failure is a refrigerant leak, which can cause the compressor to overheat and fail, costing £1,500–£3,000 to replace (Energy Saving Trust, 2026). A dirty outdoor coil can reduce the heat pump’s CoP from 3.0 to 2.5 or lower, increasing running costs by roughly 15–20%.
Some manufacturers will void the warranty on the compressor (the most expensive component) if an annual service record cannot be provided. For example, Vaillant requires an annual service by an MCS-certified engineer to keep the compressor warranty valid. Without that record, you would pay the full replacement cost out of pocket.
Eligibility for the Smart Export Guarantee (SEG) and how it relates to maintenance
If your air source heat pump is part of a solar-plus-heat-pump system, you may be eligible for the Smart Export Guarantee (SEG), which pays you for excess electricity exported to the grid (GOV.UK, 2026). To qualify, your installation must be MCS-certified, and you must maintain that certification by keeping the system in good working order.
A poorly maintained heat pump can reduce your export earnings because it may draw more electricity than necessary, leaving less for export. The SEG rate is set by your chosen energy supplier and is typically 4–15p per kWh exported (Ofgem, 2026). If your heat pump is running inefficiently, it will consume more of your solar generation, reducing the amount you can sell back to the grid.
Smart Export Guarantee rates explained
Frequently Asked Questions
No, there is no legal requirement for an annual safety inspection of an air source heat pump in the UK, unlike gas boilers. However, manufacturer warranties typically mandate an annual service by an MCS-certified installer to remain valid.
Annual servicing costs between £150 and £250, according to the Energy Saving Trust (2026). Prices vary by installer and region.
Neglecting maintenance can cause a gradual drop in efficiency (Coefficient of Performance, or CoP) and, in severe cases, compressor failure which is expensive to replace. A well-maintained heat pump typically has a CoP of 3.0.
You can perform basic tasks like cleaning filters and checking for debris, but manufacturer warranties usually require an annual service by an MCS-certified installer. Self-service may void the warranty.
Manufacturer warranties typically require an annual service. Some installers recommend a check every two years for older units, but annual servicing is standard to protect efficiency and warranty cover.
No, the Boiler Upgrade Scheme (BUS) provides a £7,500 grant for installation costs only, not for ongoing maintenance or servicing. The grant is deducted by the installer on completion.
