Heat Pump Maintenance

Heat pump maintenance usually combines an annual professional service with straightforward checks between visits. Keep the outdoor unit unobstructed, follow the manufacturer’s user instructions and report changes in performance.

Electrical checks, internal cleaning and refrigerant work belong with a suitably qualified engineer.

Energy Saving Trust recommends servicing according to the manufacturer’s instructions, usually once a year. The exact work depends on your heat pump and the heating system connected to it. Energy Saving Trust’s maintenance guidance.

This guide focuses on domestic air-to-water heat pumps, which supply radiators or underfloor heating and may also heat a hot-water cylinder. Air-to-air and ground-source systems have some different maintenance needs, explained below.

How often does a heat pump need servicing?

An annual professional service is the usual starting point, but follow the interval specified for your equipment and warranty.

Booking in spring or summer can help you address problems before colder weather arrives. Worcester Bosch recommends this timing for its heat pumps and hybrid systems. However, do not delay an overdue service or an existing fault simply to reach a preferred season. Worcester Bosch servicing guidance.

Between services, pay attention to the outdoor unit and controller. Falling leaves, nearby gardening work or a new fault message may call for a check sooner than your normal routine.

A service and a repair appointment are different. If the system has stopped working, tell the provider when booking so they can arrange diagnosis rather than assume they are servicing an operational appliance.

What maintenance can you do yourself?

Homeowner maintenance should stay within the tasks described in your equipment’s user manual. You should not need to remove service panels or reach inside the unit.

Keep the outdoor unit clear

Look for leaves, overgrown plants, bins, bikes or garden furniture restricting the space around the heat pump. Keep the installation’s specified airflow and access clearances available.

Remove loose debris from the surrounding ground where you can do so safely. Leave debris caught behind guards or inside the equipment to an engineer. Check that nearby drainage is not covered by leaves.

There is no single clearance distance suitable for every model. Use the installation information supplied with your system rather than a generic measurement. Worcester Bosch’s homeowner guidance explains the importance of unobstructed airflow and clear surrounding drains. Outdoor-unit care guidance.

Read the controller and notice changes

Check for maintenance reminders or fault messages. If one appears, photograph the display and record when it happened.

For systems with a user-accessible pressure display, follow the manual’s checking instructions and specified operating range. Do not assume that a pressure figure given for another heat pump applies to yours.

Repeated pressure loss needs investigation. Constantly topping up the system can conceal an underlying problem.

Keep cleaning simple

Follow the manual for cleaning accessible external surfaces. Do not apply lubricants, adjust internal parts or use cleaning chemicals inside the equipment without manufacturer instructions.

For example, Vaillant’s uniTOWER instructions distinguish permitted user care from maintenance and repairs requiring a competent person. Your own model’s manual should provide the same boundary. Vaillant uniTOWER operating instructions.

What should a professional heat pump service include?

A service should follow the manufacturer’s schedule for the specific model and connected system.

Typical areas to ask about include:

• Outdoor equipment: condition, airflow restrictions and cleaning where required.

• Heating circuit: visible leaks, system pressure, circulation and relevant filters.

• Controls: settings, operation and recorded faults.

• Electrical safety: checks by someone qualified for the work.

• Hot-water equipment: cylinder checks where included in the booking.

• Service records: completed checks, findings and recommended follow-up work.

British Gas’s published checklist includes the controller’s fault history, magnetic system filter, expansion vessel, visible pipework and applicable cylinder checks. It also explicitly excludes repairs and replacements from its service-only product. British Gas service checklist.

Ask whether the quote covers the whole system or only the heat pump. A visit to the outdoor unit does not automatically include every cylinder, control or heating-system component.

The Domestic Heat Pump Guide makes this distinction: the heat pump itself and the wider heating and hot-water system can have different maintenance requirements. Domestic Heat Pump Guide, maintenance advice.

How much does heat pump maintenance cost?

The price depends on the equipment covered, your location and whether you are booking routine servicing or fault diagnosis.

As one published example, Devon-based AGV lists a heat-pump annual service at £210 including VAT. Its terms assume the appliance is operational and charge replacement parts and consumables separately. Confirm cylinder coverage and any travel charges when booking. AGV service prices, checked 1 October 2026.

This is one provider’s advertised price, not a UK average or an iHeat price.

When comparing quotes, ask each provider to confirm:

• Total price: including VAT and any travel charge.

• Cylinder coverage: whether the hot-water cylinder is included.

• Cleaning and consumables: what is included in the advertised service.

• Faults discovered during the visit: what happens next.

• Additional charges: diagnostic time, replacement parts and repair labour.

• Paperwork: the service documentation you will receive.

Compare the work included, not just the headline price. A cheaper visit may have a narrower scope. A more expensive package may include cover or support that you do not need.

Is a maintenance plan worth considering?

Compare the annual total and exclusions, rather than the monthly payment alone.

A plan may simply spread the cost of servicing. Another may add repairs, remote support or priority appointments, but still exclude particular components or charge for call-outs.

For example, British Gas distinguishes its annual service from heating-system cover, and its cover excludes repair or replacement of the heat pump itself and its controls. Read the wording carefully before assuming “heating cover” protects every part of your system. British Gas inclusions and exclusions.

Does servicing affect the warranty?

Regular servicing is often a condition of the manufacturer’s warranty or guarantee. Check the terms supplied with your installation for the required interval, engineer requirements and evidence you must retain.

Keep your installation paperwork, service reports and invoices together. A payment receipt alone may not explain which equipment was checked or what work was completed.

Vaillant’s guarantee terms, for example, set conditions that must be met for a claim to be accepted. Do not assume that another manufacturer uses identical conditions. Vaillant heat-pump guarantee terms.

Is frost or water around the outdoor unit a problem?

Frost, a brief cloud of water vapour and water beneath an air-source heat pump can be part of normal defrosting.

Vaillant explains that its aroTHERM plus uses a de-icing cycle to clear ice from the outdoor heat exchanger. Water and visible vapour can appear during that process. These signs alone do not establish a fault. Vaillant’s explanation of defrosting.

Persistent heavy ice, declining heating performance or a recurring fault message should be assessed. Photograph what you see and contact your installer or service provider. Avoid attempting to remove ice from the equipment yourself.

Do not routinely disconnect the electricity supply to prevent winter running. Some protective functions depend on the system remaining powered. Follow the manufacturer’s instructions for holidays, shutdowns and frost protection. Vaillant frost-protection guidance.

When should you contact an engineer?

Arrange advice if you notice:

• Repeated faults: recurring messages or unexplained shutdowns.

• Reduced comfort: heating or hot water that no longer meets your normal needs.

• Pressure problems: repeated loss of system pressure.

• Unusual noise: new, persistent mechanical sounds.

• Visible problems: damage or a suspected leak.

• Changing consumption: a substantial unexplained increase in electricity use.

These observations do not identify the failed component on their own. An engineer needs to assess the equipment, controls and connected heating system.

For a suspected electrical hazard, such as burning smells or repeated electrical tripping, stop using the equipment and seek urgent professional advice. Do not remove covers or repeatedly reset it.

When contacting the provider, have the model, displayed fault code, last service date and a short description of the change ready. Say whether the problem affects heating, hot water or both.

Do other heat pump types need different maintenance?

Air-to-air heat pumps

Air-to-air systems heat or cool rooms through indoor air units. They commonly have accessible air filters with cleaning instructions in the user manual.

Daikin’s air-to-air maintenance guidance includes filter care and annual professional servicing. That filter advice should not be applied automatically to an air-to-water system supplying radiators.

Not every filter can be washed: follow the instructions for its type. Daikin air-to-air maintenance guidance.

Ground-source heat pumps

Ground-source systems need checks relevant to their ground circuit, rather than an outdoor air fan.

Energy Saving Trust identifies ground-loop antifreeze concentration, pressure and flow-and-return temperatures as additional servicing checks. Ask for a quotation covering your particular ground-source installation. Energy Saving Trust’s ground-source servicing guidance.

Hybrid systems

A hybrid installation combines a heat pump with another heat source, such as a boiler. Both appliances need appropriate maintenance; a heat-pump service does not replace the boiler’s service. Worcester Bosch hybrid servicing guidance.

How do you choose someone to service your heat pump?

Start with the original installer or manufacturer’s support team, then confirm that the engineer has experience with your model, controls and refrigerant type.

Ask what qualifications apply to the proposed work. Refrigerant work involving fluorinated gases requires the relevant F-gas qualifications. Do not assume every heat pump contains the same refrigerant or that one credential covers every task. Government guidance on F-gas qualifications.

Before the visit:

• Share your records: installation paperwork and previous service reports.

• Explain any symptoms: include fault codes and when the problem started.

• Provide access: make the outdoor unit and indoor equipment accessible.

Your next step: check the last service date and manufacturer’s schedule, then request an itemised quote covering the equipment you actually have.