Why annual servicing matters
Air conditioning systems lose efficiency gradually and often invisibly — a dirty filter or coil can increase running costs by 20% or more before it’s ever noticeable as reduced cooling. Beyond efficiency, most manufacturer warranties explicitly require proof of annual servicing to remain valid, and UK F-Gas regulations require regular leak checks on systems above a certain refrigerant charge, making servicing a legal requirement for many commercial systems and best practice for residential ones.
What’s included in a typical service visit
A standard service covers cleaning or replacing the indoor unit’s filters, inspecting and cleaning the evaporator and condenser coils, checking refrigerant pressure and topping up if within the manufacturer’s tolerance, clearing the condensate drain to prevent leaks, and testing electrical connections and controls. A good engineer will also check the outdoor unit’s surroundings for obstructions that restrict airflow, such as overgrown planting or accumulated debris.
Typical servicing costs
A single-system residential service typically costs £70–£120. Multi-split systems with several indoor units cost proportionally more, usually £100–£220 depending on the number of units. Commercial systems and service contracts covering multiple visits a year are priced separately and vary considerably with system size.
Signs your system is overdue
Musty smells when the unit starts up, noticeably weaker airflow than when the system was new, ice forming on the indoor unit, or a sudden jump in running costs without a change in usage are all signs a service is overdue. Left unaddressed, most of these issues get more expensive to fix the longer they’re left, since a struggling compressor working harder than it should is the component most likely to fail entirely.
How often should servicing happen
Once a year is the standard recommendation for residential systems, ideally in spring before peak summer demand. Commercial systems in continuous use, or systems in dusty environments, may benefit from twice-yearly servicing.