Air Conditioning Annual Service: What’s Included

By the AirCon Doctor team · Updated 30 October 2026

Air conditioning keeps working long after it starts to struggle, so problems creep up quietly: a little less cooling, a faint smell, a drip on a hot day. An annual service catches those early, keeps the system efficient and gives you a record of its condition.

Here’s what our annual service covers, in the order we usually do it.

1. Talk to you first

We start by asking how the system has been running. Any error codes, noises, smells, drips or rooms that don’t reach temperature? That tells us where to look harder. We also note the model, refrigerant type and charge from the rating plate for the records.

2. Filters

We remove, inspect and clean the air filters, and replace any that are damaged. Some units also have secondary filters, such as deodorising or fine filters, which have their own replacement intervals in the manufacturer’s manual. Blocked filters cut airflow, reduce output and can make the indoor coil ice up. We’ll show you how to clean them between visits.

3. Indoor unit: coil, fan and drain tray

The indoor coil collects dust that gets past the filter, and its damp surface can grow mould, which is the usual cause of musty smells. We clean the coil with a suitable cleaner, check the fan barrel (the cylinder that blows air out) for build-up, and clean the drain tray. Heavily soiled fan barrels sometimes need a deeper clean, which we’ll quote if needed.

4. Condensate drain and pump

We flush the condensate pipe to make sure water drains away properly and check its fall. Where there’s a condensate pump, we test it, clean its reservoir and check its float or sensor. Blocked drains and failed pumps are behind most indoor unit leaks; see our guide to air conditioning leaking water.

Want it done properly? AirCon Doctor installs, repairs and services air conditioning and heat pumps across London and the South East, from our base in East Grinstead. We’re an F-Gas certified company and NICEIC approved. Get a fixed-price quote.

5. Outdoor unit

We clear leaves and debris, check the coil and clean it if needed, check the fan and its guard, and look at the mountings, brackets and base. We check that the unit still has the clearances the manufacturer’s manual sets out, because new fences, sheds and planting often creep in. In coastal areas we pay extra attention to corrosion.

6. Refrigerant circuit performance

We check the system’s running temperatures and pressures against what we’d expect for the conditions, and look for signs of leaks at visible joints, valves and flare connections. A system that’s short of refrigerant has a leak somewhere, and the right fix is to find and repair it rather than keep topping up. See our regas page.

Where the charge is 5 tCO2e or more, a leak check is a legal requirement at least every 12 months, as set out in GOV.UK’s leak checking guidance. We record it in the F-Gas log. A typical home split on R32 is below that threshold, but we still look for leaks.

7. Electrics and controls

With the power isolated, we check terminals and connections for tightness and signs of overheating, and look at the isolator and cabling. Then we test the controls: remote, wired controller or app, timers, modes and louvres. We check the system runs in both cooling and heating if it’s a heat pump.

8. Performance test and report

Finally we run the system and measure air temperatures at the indoor unit, then write up what we did, what we found and anything we recommend. If there’s a fault, we explain the options and give you a price before doing any repair.

How often, and what it costs

For most homes, once a year is right. Systems that run long hours, sit in dusty or greasy surroundings, or serve server rooms may need more frequent visits. Some manufacturers set servicing conditions in their warranty terms, so check yours.

Our annual service is £95 to £150 + VAT, depending on the number of indoor units and access. Businesses with several systems usually use a maintenance contract. Book on our servicing page.

Quick answers

How long does an air conditioning service take?

It depends on the number of indoor units and access. A single home system is usually a short visit; multi-splits and commercial systems take longer. We give you a time when booking.

Is an annual service a legal requirement?

Not for most home systems. Leak checks are legally required from 5 tCO2e of refrigerant, which covers many commercial systems. Servicing is still good practice for every system.

Will a service top up my refrigerant?

Only if needed, and only after the leak has been found. A healthy system shouldn’t lose refrigerant.

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More advice

This guide is general information, checked against the sources linked on 30 October 2026. It isn’t legal, tax or financial advice. Rules, grants and product ranges change, so check the current position before you rely on it.