How Often Should Air Conditioning Be Serviced?
Most domestic air conditioning in London needs a proper service once a year, and heavier-use systems every six months. That is the short answer, but the honest one depends on how hard your unit works, where it sits, and whether the manufacturer's warranty has conditions attached. Here is how to work out the right interval for your own system without paying for visits you do not need.
The realistic intervals
A single split system in a Fulham flat or terraced house, used mainly for cooling in summer and the odd cold snap, is generally fine on an annual service. Book it in spring, ideally March or April, so any fault is found before the first proper hot spell rather than during it.
Step the frequency up if the system works harder. Anything running as a heat pump through winter as well as cooling in summer is effectively on duty most of the year, and six-monthly checks make more sense. The same goes for multi-split systems serving several rooms, home offices where the unit runs most of the working day, and any kit in a loft conversion that takes the brunt of the afternoon sun.
- Single split, seasonal cooling only: once a year
- Year-round heating and cooling: every six months
- Home office or heavy daily use: every six months
- Small commercial, salons, cafes, server rooms: every three to six months
- Filters cleaned by you: every four to eight weeks in season
Why London properties are harder on aircon
Outdoor condensers around Fulham are frequently squeezed into small rear courtyards, side returns or on flat roofs facing a busy road. Traffic soot, brake dust and pollen build up on the condenser coil far quicker than they would on a rural site, and a clogged coil forces the compressor to work harder for less cooling. That shows up on your electricity bill long before the unit actually fails.
Plane trees and the plaster dust from the near constant refurbishment work in the borough add to it. If your outdoor unit sits under greenery or you have had building work done in the last year, treat that as a reason to bring the service forward rather than push it back.
What a proper service should include
A service is not simply a filter wipe and a sticker. Ask what is actually being done, because the difference between a twenty minute visit and a thorough one is significant. Expect roughly an hour to ninety minutes for a single split.
You should also expect a written record of refrigerant checks. Under F Gas rules, anyone working on the refrigerant circuit must be qualified to do so, and it is entirely reasonable to ask to see that before work starts.
- Filters cleaned or replaced, indoor coil and blower wheel checked
- Condensate drain and pump flushed and tested, no standing water in the tray
- Outdoor condenser coil cleaned, fins straightened, clearances checked
- Refrigerant pressures and superheat checked, leak test on the circuit
- Electrical connections tightened, running current compared to nameplate
- Temperature split across the indoor coil measured and recorded
Signs you should not wait for the next service
Some symptoms mean booking sooner rather than sticking to the calendar. A musty smell when the unit starts usually points to biological growth on the coil or a blocked condensate drain, which is a health issue as much as a performance one. Water dripping from the indoor unit is almost always a drain problem and will damage plaster and flooring if left.
Ice on the pipework, a system that runs constantly without reaching the set temperature, or a noticeable jump in electricity use all suggest low refrigerant or a fouled coil. Low refrigerant means a leak somewhere, and a leaking system loses efficiency steadily while it slowly damages the compressor. Topping it up without finding the leak is not a repair.
Cost, warranty and the honest trade-off
As a broad guide, an annual service on a single split system in South West London typically falls somewhere in the region of one hundred to one hundred and eighty pounds plus VAT, with multi-split systems priced per indoor unit and usually cheaper per head. Quotes vary with access, roof work and how many units are on site, so treat any figure given before someone has seen the job as indicative only.
Check your paperwork too. Most manufacturers make annual servicing a condition of the extended warranty on their equipment, so skipping a year to save the fee can quietly cost you a compressor claim later. Set against that, a well maintained system typically holds its efficiency and often reaches twelve to fifteen years, while a neglected one starts struggling well before ten.
Common questions, plainly answered
Can I just clean the filters myself instead?
Cleaning filters yourself every four to eight weeks during heavy use is genuinely worthwhile and takes a few minutes. It does not replace a service, though, because it cannot check refrigerant pressures, electrical connections or the condensate drain.
What if I barely used the aircon last year?
Light use does not mean no service, as seals dry out, refrigerant can leak slowly from an idle system, and drains silt up regardless. An annual check is still sensible, though a system that has sat unused may need little more than a clean and a pressure test.
Is servicing a legal requirement for my home?
For a domestic system there is no legal duty to have it serviced, although only an F Gas qualified engineer may work on the refrigerant circuit. Commercial systems above certain refrigerant charges do carry mandatory leak checking obligations on the owner.