A single-room air conditioning installation typically takes three to five hours, so a morning or afternoon appointment rather than a full day off work. Add a second room and you are looking at five to eight hours, usually a full day. Three or more rooms usually means the installer books two days. Ducted whole-house systems run three to five days because separate trades are involved.
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Get a free air conditioning installation quoteHow long different installations take
These are typical durations for a competent installer working without complications. They are not guarantees, and any individual job can run longer for reasons covered below.
- Single-room split system: 3 to 5 hours
- Two-room multi-split: 5 to 8 hours, one full day
- Three-room multi-split: 1.5 to 2 days
- Four or five-room multi-split: 2 to 3 days
- Ducted whole-house system: 3 to 5 days, separate trades involved
If an installer quotes a single-room job at a full day with no clear reason, ask what is filling the extra time. It may be legitimate, for example a difficult outdoor unit location, but it is a fair question to ask before you book.
What makes installations take longer
Wall construction
Solid stone or thick masonry takes longer to drill through than brick or a stud partition wall. If your home is an older stone-built property, factor in extra time versus a standard 1990s brick build.
Pipe run length and complexity
A straight pipe run through one wall is quick. A run with several bends around structural elements, or one that has to travel a long distance to reach the outdoor unit, adds time.
Outdoor unit location
Ground mounting on a bracket is faster than roof mounting or a location with difficult access, such as a flat roof reached only by scaffold tower or a rear garden with no side access.
Electrical work
Connecting to an existing dedicated circuit is fast. Modifying the consumer unit or running a new circuit needs an electrician and typically adds half a day or more to the job.
Making good
If the installer includes making good, meaning plastering and painting around the wall penetration, add roughly one to two hours per penetration point on top of the installation itself.
Installations sometimes run over. A wall turns out thicker than expected, a pipe run hits an unexpected obstacle, or electrical work uncovers a consumer unit issue. A professional installer should tell you as this develops rather than leaving a job half finished. Ask upfront what happens if the work runs significantly longer than quoted, before you sign anything.
The difference between installation time and lead time
Installation time and lead time are two different things, and conflating them is where most people’s expectations go wrong. The installation itself for a single room takes four hours. The process from first contact to a completed installation typically runs three to eight weeks in normal conditions, longer during peak season.
A survey visit, usually thirty to sixty minutes and normally a separate appointment, has to happen before installation day in all but the simplest jobs. During summer 2026, with heatwave demand still active, many installers in the south east are quoting six to ten weeks just for a survey slot. That figure is based on current market conditions rather than a published source, so treat it as indicative rather than fixed, and ask any installer you contact for their actual current lead time.
This is the real planning point: booking now for an autumn slot generally means a September survey and an October or November installation, not a summer one. There is a separate page on the best time of year to get air conditioning quotes if timing your booking is the main thing on your mind.
Do you need to be home?
Yes, at the start of the day to confirm unit placement and pipe routing, and at the end for handover and the demonstration of controls. You do not need to sit and watch the entire job, but being reachable by phone during the day is sensible in case a decision needs to be made partway through, for example if an obstacle changes the plan.
How to plan your installation day
Clear access to both the indoor wall and the outdoor unit location before the installer arrives. Expect some noise and dust around the drilling stage. If making good is included, allow the paint to dry before moving furniture back. For anything beyond a single room, block out the full day rather than assuming you can work around a morning appointment.
If you want the full walkthrough of what actually happens on the day itself, that is covered in our separate guide on what happens during a split AC installation.
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