Good Houses
Air conditioning cost calculator
Step 1 of 3
Where's the property?
A postcode gives you figures for your actual area. You can also skip this and get a regional estimate.
This is a middle figure rather than a fixed one. There is a wide spread of units on the UK market, and premium brands such as Daikin and Mitsubishi cost noticeably more upfront while typically lasting a good deal longer. That is a judgement about how long you plan to stay, not about who installs it cheapest.
Two things change the number more than the unit itself. The first is how many rooms you want covered, and whether one outdoor unit can serve all of them, which usually works out cheaper overall than separate systems. The second is where the pipework runs. Taking it up through the loft instead of across the outside wall looks far better, but it costs more, and the extra distance can mean adding a small pump.
How we size cooling room by room
Sizing is done room by room rather than for the house as a whole, because a south-facing room under a roof with a large window needs far more cooling than a north-facing ground-floor room of identical size. The calculator starts from each room's floor area and adjusts it for the things that genuinely change the load: which way it faces, how much glazing it has, whether it is on the top floor or under the roof, and whether it is a kitchen.
That gives a cooling load, which is rounded up to the next real unit size, because you cannot buy a 3.1 kW unit, so quoting one would be fiction. The number of rooms then determines the system type: one room is a single split, a handful is a multi-split, and beyond that the calculator stops estimating and tells you to get a survey, because at that scale a spreadsheet is the wrong tool.
Cost is built from the outdoor unit sized to the total load, the indoor units, pipework between them, electrical work, installation labour adjusted for your area, and scaffolding where any indoor unit is above the ground floor.
The result is always a range, never a single figure. A precise number would be a false promise, because two builders quoting the same job honestly can land a long way apart. Everything is rounded rather than shown to the pound, for the same reason.
Every figure behind this comes from a table we maintain by hand and review on a schedule. The date of the last review is shown on this page, so you can judge how current it is rather than take our word for it.
What the air conditioning figure covers
The figure covers:
- The outdoor unit, sized to the total cooling load
- Indoor units, one per room
- Pipework between indoor and outdoor units
- Electrical work
- Installation labour, adjusted for your area
- Scaffolding, where any indoor unit is above the ground floor
What the air conditioning figure leaves out
Not in the figure:
- Planning permission for the external unit, which is likely if you are listed or in a conservation area
- Building work to create a route for the pipework
- Making good and redecorating where pipework passes through rooms
- Upgrading your electrical supply if it will not carry the system
- Annual servicing, which these systems need
- Acoustic screening if the outdoor unit sits near a boundary
If you tell the calculator the property is listed or in a conservation area, or that you are not sure, it will flag the planning question prominently rather than leave it in the small print.
Why air conditioning costs more in some regions
Labour is the part of an air conditioning installation that moves most by region, so it is the part we adjust. Every area carries a labour multiplier, and the calculator applies it to the labour element rather than to the whole figure, because materials cost broadly the same everywhere, and scaling them by region would overstate the difference.
Where we hold published data for your area, that area's own multiplier is used. Where we do not, the calculator falls back to the figure for your region and the page says so. It will never quietly borrow a nearby city's numbers and present them as local. A London figure on a Cumbrian postcode is worse than no figure at all.
Taking this to F-Gas certified installers
Take it to real quotes, and treat it as the shape of the answer rather than the answer. Get three written quotes from F-Gas certified installers, which is a legal requirement for this work, and compare what each one includes before you compare the totals, because the cheapest number on the page is often the one leaving the most out.
If a quote comes in below our range, that usually means a newer business building a reputation, or work that cuts corners. Above it usually means limited local supply, or a firm with higher overheads. Both can be the right choice. The question worth asking is what is included, not why the number differs.
Worth asking every firm you speak to:
- Where exactly will the outdoor unit go, and how loud is it at the boundary?
- What route does the pipework take, and what has to be made good afterwards?
- Are you F-Gas certified, and can I see it?
- Does this need planning permission where I live?
- What does servicing cost, and how often?
Common questions
Do I need planning permission?
Often not for a straightforward installation, but the external unit is the issue, and the rules tighten considerably for listed buildings and conservation areas. The calculator flags it when you tell us either applies, including when you are unsure, because that is the case worth checking rather than assuming.
Can it heat as well as cool?
Most modern systems can, and run efficiently doing it. Whether that makes sense against your existing heating depends on what you have now. Our heat pump calculator is the better tool for that comparison.
Why does the estimate stop at six rooms?
Because beyond that, sizing genuinely needs a survey. Pipe runs, unit placement and load balancing stop being predictable from room dimensions, and a number produced without that would be a guess dressed up as an estimate.
Is this a quote?
No. It is an estimate built from typical costs, and no contractor is bound by it. Use it to know whether a quote you have been given is roughly where it should be, and to walk into that conversation knowing what questions to ask.
Why do you show a range instead of one number?
Because one number would be misleading. The answer to "what will this cost" is a range, and where you land inside it depends on your property, your area and who you hire. Any tool giving you a single figure to the pound is telling you something it cannot know.
Do you save what I type in?
No. The calculation runs and the answers are discarded. Nothing is written down unless you explicitly ask us to email or save a result. We do not build a profile from calculator use.
How current are the figures?
The date of the last review is shown on this page. The costs behind the calculator are maintained by hand rather than scraped, and reviewed on a schedule.