Air Conditioning Installation in the UK
A single-room split system is installed in a day by an F-Gas certified engineer, and costs £1,500 to £3,000 fitted. This guide covers what happens on the day, what the law requires of your installer, and how to find good local companies without ringing round.
Quick Answer
Air conditioning installation takes about a day for a single room and costs £1,500 to £3,000 fitted. The engineer mounts the indoor and outdoor units, connects refrigerant pipework and cabling, pressure-tests the circuit and commissions the system. UK law requires the installer to hold F-Gas certification.
Fact-checked by John Rooney, Solar Energy Editor. Editorial policy
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What happens on installation day
Survey and positioning
The engineer confirms where the indoor unit sits (high on a wall, usually opposite the bed or seating) and where the outdoor condenser goes: an outside wall, flat roof or ground level, keeping the pipe run short.
Mounting both units
The indoor unit is mounted on a bracket, the outdoor condenser on brackets or a base. A small hole is drilled through the wall for the pipework and cables.
Pipework and electrics
Insulated refrigerant pipes, a condensate drain and power cabling run between the two units, usually in neat external trunking. Electrical work must meet Part P building regulations.
Pressure test and commissioning
The engineer vacuum-tests the circuit for leaks, releases the refrigerant, then runs the system in cooling and heating modes and shows you the controls.
A single-room install takes about a day. Multi-room systems take 2 to 3 days depending on how many indoor units are being fitted and how far the pipe runs go. See what air conditioning costs for the full price breakdown.
Why your installer must be F-Gas certified
Split systems contain fluorinated refrigerant gases. UK law requires anyone who installs, services or decommissions equipment containing them to hold F-Gas certification. This is the single most important credential to check: an uncertified install is illegal, voids most manufacturer warranties, and risks refrigerant leaks that harm both performance and the environment. Reputable installers will show their certificate without being asked twice.
This is also why the "pre-gassed" DIY kits sold online are a false economy: connecting them still involves refrigerant couplings, most manufacturers won't warranty a self-install, and you have no commissioning test to prove the system is tight.
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Check F-Gas certification
Non-negotiable and legally required. Ask for the certificate number.
Get 2 to 3 quotes
The same job can be quoted £1,000 apart. Competing quotes are the only reliable price check, especially in London where prices run 15 to 25% higher.
Ask which brand and why
Daikin and Mitsubishi Electric are the premium standards; Midea and similar value brands cost less. A good installer explains the trade-off rather than just quoting one option.
Confirm what's included
Brackets, trunking, electrical connection, commissioning and waste removal should all be itemised. Ask about the workmanship warranty on top of the manufacturer's unit warranty.
Installation cost at a glance
| Job | Typical Cost Fitted | Time |
|---|---|---|
| Single room (wall-mounted split) | £1,500 to £3,000 | 1 day |
| 2 to 3 rooms (multi-split) | £4,000 to £8,000 | 2 to 3 days |
| Whole house (ducted) | £8,000 to £15,000 | 3+ days |
Full breakdown, including the unit vs labour split and what moves the price, in our air conditioning cost guide.
Installation FAQ
How long does air conditioning installation take?
A single-room wall-mounted split system takes about a day: mounting both units, running pipework and cabling, pressure-testing and commissioning. Multi-room systems take 2 to 3 days depending on the number of indoor units.
Who can install air conditioning in the UK?
Only engineers holding F-Gas certification can legally install split air conditioning, because the systems contain fluorinated refrigerant gases. Electrical connections must also comply with Part P building regulations. Always ask to see certification before booking.
Can I install air conditioning myself?
Not legally for a split system: handling refrigerant requires F-Gas certification. So-called pre-gassed DIY kits still involve refrigerant couplings, usually void the manufacturer warranty on self-install, and skip the commissioning tests that prove the circuit is leak-free. Portable units are the only true DIY option.
How much does air conditioning installation cost?
£1,500 to £3,000 fitted for a single room, of which labour is £700 to £1,200. A multi-split covering 2 to 3 rooms costs £4,000 to £8,000 and a ducted whole-house system £8,000 to £15,000. London prices run 15 to 25% above the national average.
Do I need planning permission to install air conditioning?
It depends on the property. Rules differ for houses, flats, listed buildings and conservation areas, and the outdoor unit's position and noise levels matter. A good installer checks what applies to your property and handles any requirements before work starts.
Where should the outdoor unit go?
On an outside wall, flat roof or at ground level, as close to the indoor unit as practical to keep the pipe run short. Installers avoid positions directly outside a neighbour's window and consider noise, airflow and access for future servicing.
Sources
Last updated: September 2026
John Rooney is the founder of Solar Info and has been covering the UK solar energy market since 2023. He researches every battery and inverter brand against manufacturer datasheets, MCS and Ofgem data, and feedback from the MCS-certified installers in our directory before publishing.
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