The annual air conditioning maintenance checklist every London property needs

Air conditioning is mechanical equipment running for thousands of hours a year. Left unserviced, efficiency drops, noise rises and small faults become expensive failures — usually during the first hot week of the year.

Filters and airflow

Blocked filters are the single most common cause of poor performance. They restrict airflow, ice the coil and force the compressor to work harder for less output.

• Remove, wash and dry indoor filters
• Inspect the evaporator coil for fouling
• Check fan speed and airflow across each grille

Refrigerant and compliance

Refrigerant handling is legally restricted to F-Gas certified engineers. A correct service records charge, checks for leaks and logs the results where the system exceeds the regulated threshold.

“A system losing refrigerant is not just inefficient — it is a compliance issue and, for commercial sites, a records issue too.”

Drainage and condensate

Condensate pumps and drain lines cause more ceiling damage than any other part of a split system. Flushing lines and testing float switches annually prevents almost all of it.

Electrical and controls

1. Check terminal tightness and insulation
2. Verify running current against manufacturer data
3. Test controls, schedules and remote functions
4. Confirm safe isolation and outdoor unit condition

Most residential systems need one visit a year. Commercial and heavily used systems generally need two. Either way, keep the records — they matter for warranty claims.