Air Conditioning Maintenance: What You Need to Do Each Year
Annual maintenance keeps your system running efficiently, extends its life and maintains your warranty. Here's exactly what's involved.
An air conditioning system is a precision mechanical device. Like any mechanical system, it benefits from regular maintenance — and the consequences of neglect build up gradually before causing an obvious failure at the worst possible time.
What you can do yourself
The one maintenance task that every owner should perform is filter cleaning. Most split systems have a washable filter behind the front panel of the indoor unit. This filter collects dust, pet hair and airborne particles and should be cleaned every 4–6 weeks during periods of heavy use.
- •Turn the system off and remove the front panel
- •Slide out the filter (usually clips out easily)
- •Wash the filter in warm water and mild detergent
- •Allow to dry completely before refitting
- •A dirty filter can increase energy consumption by 10–20% and reduces cooling/heating performance
What an annual professional service covers
A professional annual service goes significantly beyond what an owner can do themselves. A qualified F-Gas engineer will carry out:
- •Full filter inspection, clean or replacement
- •Indoor unit coil clean (removes mould, bacteria and dust buildup that a filter doesn't catch)
- •Condensate drain flush (prevents blockage and overflow)
- •Outdoor unit inspection and coil clean (critical for efficiency)
- •Refrigerant pressure check and leak test (F-Gas legal requirement)
- •Electrical connection check (loose terminals are a cause of compressor failure)
- •Operating controls and sensor calibration check
- •Performance test confirming system is operating to specification
Why the refrigerant check matters
The refrigerant in your system is sealed — it should never need topping up under normal operation. If a system requires refrigerant, it means there's a leak. This is not just an efficiency issue; refrigerant gases are potent greenhouse gases, and discharging them to atmosphere is illegal. Regular leak checks catch small leaks before they cause compressor damage or become an environmental issue.
Under UK F-Gas regulations, systems containing 3kg or more of refrigerant must be leak-checked at least annually by an F-Gas certified engineer. Most domestic split systems contain less than this, but an annual service is still best practice and maintains your manufacturer warranty.
Signs your system needs attention between services
- •Ice forming on the indoor or outdoor unit
- •Water dripping from the indoor unit (blocked condensate drain)
- •Unusual noises (clicking, grinding, gurgling)
- •Error codes displayed on the indoor unit
- •Noticeably reduced cooling or heating performance
- •Unpleasant odour when the system runs (mould in indoor unit)