The Short Answer: Annually
Every heat pump manufacturer recommends annual servicing. This isn't a suggestion — it's typically a condition of your warranty. Skip a service and you risk voiding warranty coverage on a system that cost £8,000–£15,000 to install.
Beyond warranty requirements, annual servicing catches small problems before they become expensive failures. A £150 service can prevent a £2,000 compressor replacement.
What a Proper Service Includes
A genuine heat pump service — not just a visual check — should include: refrigerant pressure and temperature checks, electrical connection tightness testing, filter cleaning, condensate drain inspection, flow temperature verification, COP measurement, and a functional test of all operating modes including defrost.
If your engineer isn't measuring refrigerant pressures and calculating COP, you're not getting a proper service. These measurements are the only way to verify the system is operating efficiently and catch refrigerant leaks early.
F-Gas Compliance Requirements
Systems containing fluorinated greenhouse gases above certain thresholds have legal inspection requirements under the F-Gas Regulation. Most residential heat pumps fall below the mandatory leak check threshold, but proper record-keeping of refrigerant quantities is still a legal requirement.
Your service engineer should provide documentation of all refrigerant handling — charges, recoveries, and leak checks. This documentation may be required if you sell your property or if the system is decommissioned.
Signs Your System Needs Attention Between Services
Don't wait for your annual service if you notice: unusual noises from the outdoor unit, ice forming on refrigerant pipes, the system running continuously without reaching temperature, error codes appearing on the controller, or a noticeable increase in electricity consumption.
Early intervention on these symptoms almost always costs less than waiting. A small refrigerant leak detected early might cost £200 to repair. Left six months, the compressor damage could cost £2,500.