UK Heat Pump Servicing: What Gets Checked and What It Costs in 2026

TL;DR:

• Annual heat pump servicing typically costs £150–£300 and is usually required to keep your manufacturer warranty valid
• A full service covers refrigerant pressure, electrical connections, filters, flow rates, and controller calibration
• You can do basic checks yourself (clearing the outdoor unit, checking filters, reviewing system temperatures) — but refrigerant work requires an F-Gas certified engineer

Your heat pump is a sealed refrigeration system with moving parts, electrical components, and a pressure circuit. Like any mechanical system, it benefits from annual attention. Most manufacturers require at least yearly servicing as a condition of their warranty — skip it and you may find a repair bill landing entirely on you.

Here is what goes into a proper service, what it costs, and how to make sure you’re getting value for money.

What a Full Heat Pump Service Covers

A comprehensive annual service from a qualified engineer should include the following.

Outdoor unit inspection

The outdoor unit draws heat from the air (for air source systems) or from the ground loop fluid (for ground source). The engineer will:

• Clean the heat exchanger coils of debris, dirt, and organic matter
• Check that the fan blades are undamaged and rotating freely
• Inspect the casing and mounting for corrosion or loose fixings
• Clear any obstruction around the unit that could restrict airflow

Refrigerant circuit checks

The refrigerant circuit is the core of the system. An F-Gas certified engineer will check operating pressures against the manufacturer’s expected values at current outdoor conditions. Low pressure indicates a potential leak or undercharge. They cannot top up refrigerant without identifying and fixing the source of any leak — the F-Gas regulations prohibit releasing refrigerant to atmosphere and require leak checks on systems above certain charge sizes.

Note: homeowners cannot legally handle refrigerants. Any refrigerant work, including pressure testing, must be done by an engineer holding an F-Gas qualification.

Electrical and control system

• Check all electrical connections for tightness and signs of corrosion
• Test defrost cycles function correctly (for air source systems operating in winter)
• Verify thermostat and programmer settings are correct for the season
• Check flow and return temperature sensors are reading accurately
• Review error logs on the heat pump controller for any historic faults

Hydraulic circuit (heating system side)

• Check system pressure in the sealed heating circuit (typically 1.0–1.5 bar when cold)
• Inspect the expansion vessel pre-charge pressure
• Check the pressure relief valve is not weeping
• Verify flow rate through the heat pump meets manufacturer specifications
• Inspect the plate heat exchanger (for systems using one) for scaling

Filters and strainers

Most systems have a Y-strainer or magnetic filter on the return pipe to catch debris from the heating circuit. These need cleaning annually — a blocked filter reduces flow and efficiency. If you have a system filter with an isolation valve, some engineers will show you how to do this yourself between services.

Coefficient of performance review

A useful addition to any service is a review of your system’s actual performance against what it should be achieving. Your heat pump’s controller typically logs flow temperature, return temperature, energy input, and heat output. An experienced engineer can review this data and tell you whether your system is performing efficiently or whether changes to settings (flow temperatures, schedules) could improve performance.

What You Can Check Yourself

There are checks you can and should do yourself between services — not to replace an engineer visit, but to catch obvious problems early.

Monthly:

• Check the system pressure gauge on your cylinder or manifold. If it has dropped below 1 bar, the system needs topping up (you can do this yourself with the filling loop — check your manual).
• Look at the outdoor unit. Clear any leaves, weeds, or debris that have accumulated around it. Maintain at least 30cm clearance on the intake side.
• Check the temperature readings on your controller against recent outdoor temperatures. If the system is struggling to reach setpoint on mild days, something may be wrong.

Before winter:

• Confirm your antifreeze inhibitor concentration is adequate. Ground source systems and some air source buffer tanks need glycol at concentrations appropriate for your local minimum temperatures.
• Check that drain holes on the outdoor unit are clear — blocked drains cause ice to build up during defrost cycles.
• Review your heating schedule and adjust for the season.

Annually (before your service visit):

• Note any error codes or warning lights that have appeared on the controller. These give your engineer a head start.
• Review your electricity consumption. If usage has increased significantly compared to the same period last year with similar weather, it warrants investigation.

What Heat Pump Servicing Costs

Prices vary by region, system type, and installer. As a guide for 2026:

Some installers offer annual service contracts at a fixed monthly cost, which can include emergency call-out cover. These typically cost £15–£30/month and make sense if you want predictable maintenance costs and priority support in winter.

These prices do not include any parts. If your service reveals a failing component — a circulation pump, a sensor, or a failing fan motor — parts and labour for repairs are additional.

Who Should Service Your Heat Pump

Your heat pump should be serviced by an engineer who:

• Holds an F-Gas qualification (mandatory for refrigerant circuit work)
• Is familiar with your specific brand and model (not all heat pump engineers have experience across all manufacturers)
• Is ideally MCS-accredited or working for an MCS-accredited company

For the first few years, returning to your original installer for servicing makes sense — they know your installation and can identify anything that was not set up correctly at commissioning. Once your warranty period has passed, you can shop around.

To find qualified engineers, check:

• Your manufacturer’s website (most have installer/service directories)
• The MCS installer database at mcscertified.com
• Heating engineer trade bodies including Gas Safe Register (for combined installations with gas backup)

Avoid general plumbers or heating engineers who claim to service heat pumps without specific refrigeration/F-Gas qualifications. Incorrect handling of the refrigerant circuit can damage the compressor and invalidate your warranty.

Warranty Implications

Most heat pump manufacturers require evidence of annual servicing to process warranty claims. If your compressor fails in year four of a five-year warranty and you cannot produce service records, you may find the manufacturer declining the claim.

Keep service records with:

• Date of service
• Name and F-Gas certificate number of the engineer
• Work carried out
• Any findings or recommendations

Some manufacturers provide a service log booklet with the installation. Use it.

Common Problems Found at Service

The most frequent issues discovered at annual heat pump services:

• Clogged filters reducing flow rate and causing the system to short-cycle
• Low system pressure from a small hydraulic leak or a poorly pressurised expansion vessel
• Incorrect flow temperature settings from a commissioning that was not optimised for the specific property
• Refrigerant pressure at the lower end of specification — not yet a leak, but worth monitoring
• Controller settings reverting to factory defaults after a power cut, causing the system to run at inefficient temperatures

Most of these are inexpensive to address when caught at service. Left untouched, several can progress into more costly failures.

Annual servicing is one of the smaller ongoing costs of heat pump ownership. At £150–£250 per year, it is considerably less than a boiler service on a gas system and a fraction of what a compressor replacement or refrigerant recharge costs if problems develop undetected.