Most air source heat pumps should be serviced once a year, although you should always follow the schedule stated by the manufacturer and in your warranty documents. An annual service helps protect the warranty, spot developing faults and confirm that the system is still heating your home efficiently.
Unlike a gas boiler, a heat pump does not burn fuel. That does not make it maintenance-free. It is a complete heating system containing an outdoor unit, pumps, valves, filters, controls, electrical components and usually a hot-water cylinder. All of these need to work together properly.
The short answer
Book your first heat pump service around 12 months after commissioning and continue annually. If the manufacturer specifies a different interval, follow its instructions. Enerus offers air source heat pump servicing from £165 across Northumberland and surrounding parts of the North East.
Why does an air source heat pump need an annual service?
A heat pump may continue producing heating and hot water even when its performance has started to deteriorate. A partially blocked filter, incorrect system pressure, damaged pipe insulation or poorly adjusted control setting may not cause an immediate breakdown, but it can make the system work harder than necessary.
Annual servicing gives an engineer the opportunity to identify these issues before they develop into loss of heating, higher electricity consumption or a more expensive repair.
The main reasons to arrange regular servicing are:
- Protecting the manufacturer’s warranty. Servicing requirements vary, but many manufacturers make annual maintenance a condition of their guarantee.
- Maintaining performance. The engineer can check temperatures, flow rates, system pressure and control settings rather than simply confirming that the unit switches on.
- Preventing avoidable breakdowns. Water leaks, deteriorating insulation, blocked strainers and stored fault codes can be investigated early.
- Maintaining frost protection. External water pipework needs suitable insulation and the system’s intended frost-protection measures must remain effective.
- Keeping records. A completed service record demonstrates that the system has been maintained and provides useful history for future fault-finding.
Vaillant currently advises that its heat pumps are serviced once a year. Its UK guarantee terms state that servicing must be completed annually by a suitably competent engineer and recorded in the Benchmark logbook. Requirements differ between manufacturers, so your own installation and warranty documents remain the final authority.
What should an air source heat pump service include?
A proper service should examine the heating system as a whole—not just look at the outdoor fan unit. The exact procedure depends on the manufacturer, model and system design, but a thorough visit will normally include the following areas.
1. Outdoor heat pump inspection
The engineer should inspect the casing, fan, coil and surrounding area for damage, dirt or restricted airflow. Leaves, vegetation and other debris can reduce airflow through the evaporator.
The unit’s mounting, feet or brackets should also be checked. Excessive movement or vibration may indicate a problem that requires attention.
2. External pipework and insulation
Flow and return pipework outside the property is exposed to wind, rain, sunlight and freezing temperatures. The engineer should check the condition of the insulation, joints, seals and weatherproof finish.
Missing or damaged insulation can increase heat loss and leave pipework more vulnerable during cold weather. It should be repaired using materials suitable for external use rather than ordinary indoor pipe insulation.
3. Water pressure, leaks and circulation
The service should include checks for visible leaks and abnormal pressure. The engineer may examine circulating pumps, strainers or filters, expansion arrangements and relevant valves, depending on the system.
Restricted circulation can affect heat delivery and may cause the heat pump to operate at higher temperatures or cycle more frequently. Filters should only be cleaned or replaced in accordance with the system and manufacturer’s instructions.
4. Frost protection and system water quality
Different systems use different frost-protection strategies. Some contain glycol; others use anti-freeze valves, electrical protection routines or a combination of measures.
Where applicable, the engineer should confirm that the installed protection remains appropriate and check inhibitor, glycol concentration or system-water condition using the correct procedure. This is particularly important in exposed Northumberland locations where external pipework may experience prolonged low temperatures.
5. Electrical and control checks
Accessible electrical components, isolators and connections should be visually inspected and tested where the servicing procedure requires it. The engineer should also review the controller for current or historic fault codes.
Control settings matter. Weather compensation, heating curves, schedules and domestic hot-water temperatures all influence how the system operates. A service is a useful opportunity to check that settings have not been unnecessarily increased or changed since commissioning.
6. Operating temperatures and performance
Simply feeling a warm pipe is not a performance check. The engineer should run the system and review relevant operating information, which may include flow and return temperatures, temperature difference, target temperatures, sensor readings and compressor operation.
This does not recreate a laboratory efficiency test, but it can reveal whether the heat pump is behaving as expected and whether further investigation is needed.
7. Cylinder and hot-water components
If the service includes the hot-water cylinder, the engineer should inspect the associated controls and components specified by the manufacturer. Unvented cylinders have their own maintenance requirements and safety devices, so confirm whether cylinder servicing is included when booking.
8. Service record and homeowner advice
The visit should finish with a record of the checks completed, any readings taken and any recommended remedial work. Relevant manufacturer or Benchmark documentation should be updated when required.
The engineer should also explain anything the homeowner needs to monitor rather than leaving without discussing the findings.
What is the difference between servicing and repairing a heat pump?
| Heat pump service | Heat pump repair |
| Planned annual maintenance | Response to a known fault or loss of performance |
| Checks condition and operation | Diagnoses and corrects a specific problem |
| May identify developing defects | May require replacement parts or further attendance |
| Helps maintain service records and warranty | Restores heating, hot water or normal operation |
A routine service price does not normally include replacement parts or extensive diagnostic work. If a fault is discovered, the engineer should explain the issue, any immediate risk and the likely cost before undertaking additional chargeable work.
When should you book the service?
The easiest approach is to arrange the service close to the anniversary of the installation. Booking during spring or summer can be convenient because any remedial work can be completed before colder weather places the system under greater demand.
Do not wait for the annual appointment if you notice:
- Persistent warning messages or fault codes
- Unusual vibration, rattling or grinding sounds
- Regular loss of system pressure
- Water leaking from the unit or nearby pipework
- Damaged external insulation
- Rooms taking noticeably longer to warm
- Repeated use of backup or immersion heating
- An unexplained rise in electricity consumption
- Loss of heating or hot water
Some water beneath an outdoor unit can be normal during a defrost cycle, particularly in cold or damp weather. A new or persistent leak from pipework, however, should be investigated.
What can homeowners do between services?
Homeowner maintenance should remain simple. You can:
- Keep leaves, litter and vegetation away from the outdoor unit.
- Make sure airflow is not blocked by stored items, fencing or garden alterations.
- Look occasionally for damaged insulation or visible water leaks.
- Check the controller for warnings.
- Keep a note of unexpected changes in comfort or electricity use.
- Follow the manufacturer’s user instructions.
Do not remove covers, open the refrigerant circuit, alter safety devices or change installer-level settings. Never box in the outdoor unit or place an improvised cover over it while it operates. If something appears wrong, arrange a professional assessment.
How much does heat pump servicing cost?
Enerus currently offers heat pump servicing from £165. The final price can depend on the make and model, location, system condition and whether the cylinder or additional equipment is included.
Before booking, check exactly what the quoted service covers. The lowest advertised price is not necessarily good value if it only covers a brief inspection of the outdoor unit and excludes the rest of the heating system.
Book an air source heat pump service with Enerus
Enerus designs, installs, services and repairs air source heat pump systems. Our approach is based on understanding how the complete system has been designed and how it is actually operating—not simply checking whether the outdoor unit runs.
If your heat pump is approaching its annual service date, or you have inherited a system with little maintenance history, contact us to arrange an appointment.
Call: 0191 816 5305 or 01740 669 585
Email: homeservices@enerus.co.uk
Service information: Enerus Maintenance & Repair
Frequently asked questions
Do air source heat pumps have to be serviced every year?
Most manufacturers recommend annual servicing, and it may be a condition of the warranty. Check the instructions and guarantee for your particular model rather than assuming that every manufacturer uses identical terms.
Will an annual service reduce my electricity bill?
A service cannot guarantee a particular saving. It can identify issues such as restricted circulation, damaged insulation or unsuitable settings that may be affecting performance. The building, tariff, weather and how the system is used also influence electricity consumption.
Can any heating engineer service a heat pump?
Use an engineer who is suitably competent for your heat pump and the work being undertaken. The manufacturer or warranty may specify particular qualifications, certification or approved-installer status. Refrigerant work must only be carried out by someone legally qualified for that activity.
Does a heat pump service include the hot-water cylinder?
Not always. Some prices cover the heat pump only, while others include the cylinder and wider heating system. Ask what is included before confirming the appointment.
Can a heat pump be serviced in summer?
Yes. Spring and summer are often sensible times because the heating is under less demand and there is time to complete any recommended work before winter. The engineer will still need to run appropriate operating checks.
What happens if my heat pump has missed a service?
Arrange one as soon as practical and check the manufacturer’s warranty terms. Do not assume the warranty remains valid; the manufacturer will decide how a missed service affects cover.
Helpful Links
https://www.vaillant.co.uk/service/heat-pump-servicing/
https://www.vaillant.co.uk/service/your-guarantee/heat-pump-guarantee/
Vaillant professional installation and operation manual — aroTHERM plus (PDF)
Ebac Heat Pumps
Vaillant Heat Pumps
Heat Pump Quote
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Heat Pump Servicing & Repairs