How Often Should Air Conditioning Be Serviced?

For a typical domestic system in a Surrey home, once a year is the right answer. A single annual service keeps the unit running efficiently, catches small faults before they become expensive failures, and almost always satisfies the manufacturer's warranty conditions.

To be clear, this is about home air conditioning wall-mounted, ceiling-cassette or ducted systems made by the likes of Daikin, Mitsubishi Electric, Fujitsu and Samsung. It is not the same as a car air-con regas, which is a completely different job. A home system is, in fact, an air-to-air heat pump that heats as well as cools, so it works hard year-round and benefits from regular attention.

Commercial systems work far harder than a home unit running all day in an office, shop, server room or restaurant so they need servicing more often. As a rule of thumb, twice a year is the minimum for most commercial installations, and high-demand or critical systems (server rooms, kitchens, healthcare) are often serviced quarterly.

There is also a legal angle. Systems containing more than a set quantity of F-Gas refrigerant must have regular leak checks carried out by an F-Gas certified engineer, with the frequency rising as the charge size increases. As a REFCOM-registered installer, Tempest handles these checks and keeps the records you need for compliance.

A proper service is more than a quick wipe-down. A thorough visit should cover cleaning or replacing filters, washing the indoor coil and clearing the condensate drain, checking the outdoor unit and fan, inspecting electrical connections and controls, and measuring refrigerant pressures and system performance.

The two jobs that matter most for everyday running are cleaning the filters and coils and clearing the drain. Blocked filters force the system to work harder, push up your running costs and worsen air quality; a blocked drain is the single most common cause of water leaking from an indoor unit. A good engineer will also flag any early signs of refrigerant loss before it dents your efficiency.

Yes and this catches a lot of homeowners out. Most major manufacturers, including Daikin and Mitsubishi Electric, require evidence of regular professional servicing to keep their extended warranties valid. Skip the annual service and you risk a refused warranty claim later, exactly when an expensive part fails.

Keep your service records and use a properly qualified installer. Refrigerant work must legally be carried out by an F-Gas certified engineer in any case, so it is not a job for an untrained handyman. Booking a planned annual visit is the simplest way to protect both your warranty and your investment.

An unserviced system does not usually fail overnight it degrades quietly. Dirty filters and coils reduce airflow and cooling capacity, so the unit runs longer and uses more electricity to reach the same temperature. Over a season that adds noticeably to your bills.

Beyond cost, neglected systems are more likely to grow mould in the indoor unit, leak water from a blocked drain, and suffer compressor strain that can shorten the system's life. Many breakdowns we attend in summer trace back to a service that was never booked. Regular maintenance is far cheaper than an emergency repair in the middle of a heatwave.

The ideal window is spring March to May before the summer rush. Servicing then means your system is clean, efficient and ready for the first hot spell, and you avoid the long waits that build up across the South East once temperatures climb.

If your system is your main source of heating in winter via its reverse-cycle (heat) mode, an autumn service is also sensible so it is ready for the cold months. The key is consistency: pick a season, book it in annually, and the system will reward you with lower bills and a longer life.