Heat Pump Maintenance: What You Need to Know

Why Heat Pump Maintenance Matters

A well-maintained heat pump is more efficient, more reliable, and lasts longer. Unlike gas boilers, which require an annual Gas Safe service by law, heat pumps don't have a legal maintenance requirement — but they benefit significantly from regular checks. A blocked air filter, restricted airflow, or incorrect settings can reduce efficiency by 10–15% and in some cases cause premature compressor failure.

The good news is that heat pumps are mechanically simpler than boilers — there's no combustion, no heat exchanger to scale, and fewer moving parts. Most maintenance is straightforward, and much of it can be done by the homeowner.

What to Check Each Season

Autumn (October–November)

• Check the outdoor unit for leaves and debris. Clear any accumulated leaves, seed pods, or grass cuttings from around and underneath the unit. Restricted airflow is the most common cause of reduced efficiency.
• Test the defrost cycle. As temperatures start to drop, verify the unit defrosts correctly by checking for normal operation in cold weather (light ice on the coil is normal; heavy icing that doesn't clear is not).
• Review your thermostat and schedule settings. If you've been in summer mode, switch back to heating schedules. Consider enabling a weather-compensation curve if your system supports it.
• Check the hot water cylinder. Ensure the immersion heater backup is working correctly before you need it.

Winter (December–February)

• Keep the outdoor unit clear of snow and ice. Heavy snowfall can block the air intake. Brush accumulated snow away gently — never use salt or chemicals near the unit.
• Monitor your energy consumption. If bills spike unusually, it may indicate a system problem rather than just cold weather. Modern heat pumps with smart controllers (MELCloud, sensoAPP) allow you to check CoP data directly.
• Check for unusual noises. Rattling, grinding, or persistent loud operation are worth investigating. A light whooshing or periodic fan noise is normal.

Spring (March–April)

• Clean the outdoor unit coil. Use a gentle spray from a garden hose (not a pressure washer) to wash the aluminium fins. This removes accumulated dust and pollen that reduces airflow and heat transfer.
• Check for physical damage. Winter storms can dislodge vibration isolators, loosen pipe insulation, or cause minor physical damage. A visual check takes 5 minutes.
• Review your heating system performance. If you noticed cold rooms, uneven heating, or high running costs over winter, spring is the time to investigate — before you need the system again next autumn.

Summer (May–September)

• Service the hot water settings. Many homeowners reduce the hot water schedule in summer to save energy. Consider running the hot water cylinder legionella cycle (60°C for one hour) once a month if set to operate below 55°C.
• If your heat pump provides cooling: Check the indoor unit filters (split system types) and clean as required before the cooling season.
• Book your annual professional service. Summer is an ideal time — engineers are less busy and you won't lose heating during a service call.

Annual Professional Service

We recommend a professional service every 1–2 years. During a service, a qualified engineer will:

• Check refrigerant pressure and inspect for leaks
• Clean and inspect the outdoor coil thoroughly
• Check all electrical connections and controls
• Verify flow temperatures and CoP against specification
• Inspect the hot water cylinder and controls
• Check anti-freeze concentration in the system water
• Inspect and re-seal any pipe insulation showing signs of deterioration

A professional service typically takes 1.5–2 hours. As installers across Cornwall, we carry out servicing on all the heat pumps we install — contact us to book yours.

Signs Something Needs Attention

The following warrant a call to your installer rather than waiting for the next scheduled service:

• Persistent fault codes on the controller display
• The outdoor unit icing heavily and not defrosting within 30–60 minutes
• Hot water consistently failing to reach target temperature
• Significantly higher electricity bills than the same period last year
• Unusual vibration or grinding noises from the outdoor unit
• Radiators or underfloor zones that are consistently cold

How to Optimise Efficiency Year-Round

Beyond maintenance, a few operational settings have the biggest impact on efficiency:

• Use weather compensation. If your heat pump supports a weather-compensation curve (most do), this automatically lowers the flow temperature in mild weather, significantly increasing efficiency.
• Avoid frequent on/off cycling. Heat pumps are most efficient when running steadily at lower output rather than cycling on and off. Keep thermostats at a consistent temperature rather than large overnight setbacks.
• Pair with solar if you haven't already. Running your heat pump during the day on free solar electricity can cut heating running costs by 30–40%. See our guide to solar panels and heat pumps for how this works.
• Ensure your home is as well-insulated as possible. Loft insulation, draught-proofing, and secondary glazing reduce heat loss and allow the heat pump to run at lower, more efficient flow temperatures.

Getting Support in Cornwall

We install and service air source heat pumps across Cornwall — from Truro and Newquay in the west to Liskeard and Looe in the east. Whether you need a professional service, a repair, or a new installation, get in touch or call us to discuss your requirements.