How Often Should a Heat Pump Be Serviced?
An air source heat pump should have a professional service once a year. It is a low-maintenance technology — far simpler than an annual boiler service in some respects — but the annual check keeps efficiency high, catches small issues early, and is usually required to keep the manufacturer’s warranty valid.
Between services there is very little to do, which is one of the quiet advantages of a heat pump over a combustion boiler.
What a Professional Service Covers
A proper annual service includes:
- Checking refrigerant pressures and system performance
- Inspecting and cleaning the outdoor unit’s coil and fan
- Checking the condensate drain is clear
- Verifying flow rates, expansion vessel and system pressure
- Reviewing controls, weather compensation and flow-temperature settings
- Confirming the system is still running at its designed efficiency
That last point matters: a service is also a chance to re-tune the system so your SCOP — and running costs — stay where they should be.
Simple Checks You Can Do Yourself
Between annual services, a few easy habits keep things healthy:
- Keep the outdoor unit clear of leaves, snow and garden debris — it needs free airflow.
- Do not stack anything against it or box it in.
- Glance at the condensate drain in winter to check it is not blocked or frozen.
- Note any unusual noise or a drop in performance and report it.
None of this requires tools — just an occasional look.
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Servicing Protects Efficiency and Warranty
A neglected heat pump slowly loses efficiency — a fouled coil or a low charge quietly pushes your electricity use up. Annual servicing keeps performance where it was designed to be, so you keep paying the low running costs you signed up for.
Just as important, most manufacturer warranties (often 5–7 years, sometimes longer) require evidence of annual servicing. Skipping it can invalidate cover on an expensive component. A modest yearly service is cheap insurance for a 20-year asset.
The Annual Service: What Is Checked and What It Costs
A heat pump needs far less attention than people expect, but an annual service keeps efficiency high and protects your warranty. Budget around £120–£200 a year, similar to a gas boiler service.
A proper service covers:
- Checking refrigerant pressures and system performance against the original design.
- Inspecting and cleaning the outdoor coil and clearing airflow around the unit.
- Testing the antifreeze/glycol concentration in the primary circuit.
- Checking the expansion vessel, pressures, and the hot-water cylinder and its anode.
- Reviewing controls, weather-compensation curves and error logs.
Between services you can do the easy bits yourself: keep leaves, snow and vegetation clear of the unit, make sure condensate drains are not blocked, and glance at the pressure gauge occasionally. Because R290 units like the Vaillant aroTHERM Plus have fewer moving parts than a combustion boiler and no flue to corrode, they typically last 20–25 years — roughly double a boiler — provided that annual check is kept up. Skipping servicing is the fastest way to lose both efficiency and warranty cover.
Frequently asked questions
Once a year by a qualified engineer, plus occasional simple owner checks to keep the outdoor unit clear of debris. Annual servicing keeps efficiency high and is usually needed to maintain the manufacturer’s warranty.
Yes — a heat pump can lose efficiency gradually without any obvious fault, quietly raising your bills, and most warranties require documented annual servicing. The yearly check protects both your running costs and your cover.
You can and should do the simple things — keeping the outdoor unit clear and checking the condensate drain — but the annual service (refrigerant, pressures, performance, controls) must be done by a qualified engineer.
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