How Long Does Air Conditioning Installation Take? What Happens on the Day

How long air conditioning installation takes in the UK and what happens from survey to handover: the core hole, pipework, pressure test, commissioning and what to keep afterwards.

By Max Tuleberg · Founder, Vento · Last updated 25 October 2026

Founder of Vento. Worked on the tools before building the software.

A single-room air conditioner is usually installed in a day; a multi-room system typically takes one to three days. Here's what happens from the first visit to the handover, so you know what to expect.

1. The survey

A good installer visits before quoting. They measure each room, look at windows, insulation and which way the rooms face to work out the cooling and heating load, agree where the indoor and outdoor units will go, and plan the pipe route and electrical supply. You should get an itemised quote afterwards, not a single round number.

2. Before install day

Confirm the unit positions and pipe route you agreed at the survey.
Clear space around where the indoor and outdoor units will go.
Check whether you need permission — for example from a freeholder if you live in a flat — before work starts.

3. Install day

Indoor unit — a mounting plate is fixed to the wall and the unit hung on it.
Core hole — one hole per indoor unit through the outside wall for the pipes, cable and drain.
Outdoor unit — fixed on wall brackets or a ground stand, clear of obstructions.
Pipework — insulated refrigerant pipes, a power/control cable and a condensate drain run between them.
Pressure test and vacuum — the pipework is tested for leaks and evacuated before refrigerant is released.
Electrics — the system is connected to a suitable supply.

The refrigerant work must be done by an F-Gas certified engineer — it's a legal requirement, not a nice to have.

4. Commissioning and handover

The installer runs the system in cooling and heating, checks it is performing correctly, and records the details. They should then show you how to use the controls, explain how to clean the filters, and leave you the paperwork: the manuals, the warranty details and the commissioning record. Keep these — they matter for the warranty, for servicing and, where it applies, for a grant.

After installation

Clean the filters every few weeks while the system is in use and book an annual service — see air conditioning servicing. If the system heats your home and replaced your old heating, ask your installer whether it qualifies for the £2,500 Boiler Upgrade Scheme grant.

This guide is general information for UK installers, not legal or regulatory advice. Always check the current regulations and manufacturer instructions for your specific job.

Frequently asked questions

How long does it take to install air conditioning?

A single wall-mounted split in one room is usually fitted in a day. A multi-split serving several rooms typically takes one to three days, and ducted systems longer. Long pipe runs, difficult access and extra electrical work add time — your installer will give you a firm estimate at the survey.

Is installing air conditioning messy?

Less than most people expect. The main disruption is drilling one hole per indoor unit through an outside wall (typically around 65 mm) and running pipes, either hidden in the wall or neatly in trunking. A good installer uses dust sheets and makes good as they go.

Do I need to be at home during the installation?

Usually for the start, to agree unit and pipe positions, and at the end for the handover so the installer can show you how to use and look after the system.