Air conditioning servicing: when, why, what it costs

An air con unit that gets no service will still run for years. It will run poorly, drift out of warranty, and cost you more than the service in wasted electricity. Twelve months between services is standard. Every February is a good habit.

What a proper service covers

A standard domestic service takes about an hour per indoor unit plus 30 minutes on the outdoor condenser. The engineer does eight things:

• Checks the refrigerant charge against the commissioning figure. Small losses are normal. Large losses signal a leak that needs finding.
• Cleans the filters on every indoor head. Blocked filters kill efficiency and put strain on the compressor.
• Cleans the outdoor condenser coil. A season of leaves, pollen and grime cuts heat rejection by 15% or more.
• Checks the drain line for blockages. A blocked drain floods the indoor head and stains the wall below.
• Tests the compressor amp draw. High amps signal a compressor working too hard, usually because of poor refrigerant charge or a dirty coil.
• Tests the pressure switches and thermistors.
• Updates the F-Gas record in the compliance log if the system is above the reporting threshold.
• Runs the unit through cool mode and heat mode and confirms setpoint response.

You get a written report at the end. That report is the paper trail that keeps the warranty active.

What it costs

Domestic single indoor head: £120 to £180 per year. Domestic multi-split three heads: £160 to £250 per year. Small commercial cassette: £180 to £280 per year. Commercial VRF with multiple heads: £400 to £900 per year.

Cheaper than a boiler service, and adds twice as many years to the kit lifespan.

When to book

February is the sweet spot. Reasons:

• Installer diaries are quiet before spring enquiries pick up.
• You catch problems before you need cool mode in June.
• Warranty registrations run on 12-month cycles, so an annual service in the same month keeps the paperwork clean.

If your unit went in during a specific month, book the service for the anniversary. That keeps the service history tidy for resale value later.

What happens if you skip it

Two things, in order:

• Year 1: nothing. Filters get dusty. Efficiency drops by 5 to 10%. Bills creep up but nobody notices.
• Year 3: something fails. Usually a compressor, sometimes a fan motor. Warranty claim gets refused because there is no service history. Repair cost £600 to £1,200.
• Year 5: the unit is limping. Refrigerant is low. Efficiency has dropped 25%. Replacement is £2,000 in a market where a new unit costs the same as the repair.

Every serviced unit avoids that arc.

What to ask when booking

Three questions:

1. What is included in the service, and what is extra? Filter replacements sometimes cost extra. Refrigerant top-ups always do.
2. Do you provide a written report? If they will not commit to paperwork, book someone else.
3. Are you F-Gas certified? Same answer as before - if not, do not let them near the refrigerant.

Booking through Cooler Spaces

Every installer on our network offers annual services. If we introduced you to your original installer, message them directly and they will book you in. If you moved into a house with existing air con and do not have an installer, message us on WhatsApp with your postcode and unit model and we will match you with a local service engineer.