Portable vs Fitted Air Conditioning Calculator
A portable is cheap to buy and expensive to run. This works out what each option really costs you over the years you will actually use it.
Open the calculator →Portable or fitted? Work it out in 30 seconds
4 steps. Unit type, how many summers, how much you run it, and region.
How this calculator works
Portables look cheap because the whole cost is visible on day one. A fitted split hides its advantage in the running cost: a portable draws close to its full 1.0–1.5kW almost continuously and vents through a hose that lets warm air back in around the window seal, while a split modulates down to 0.3–0.7kW once the room is at temperature.
So the honest comparison is not purchase price, it is total cost over the number of summers you will actually use it. That is what this calculates.
A portable remains the right answer in a rented flat, where no external unit is permitted, or for genuine emergency cooling. The calculator will tell you when that is the case rather than pushing you toward an install.
Portable vs fitted (2026)
| Option | Typical 2026 cost | Notes |
|---|---|---|
| Portable unit | £200–£500 | No installation; draws 1.0–1.5kW near-continuously |
| Portable running cost | £90–£160 per summer | Roughly 27–40p an hour |
| 2.5kW fitted split | £1,500–£2,600 | Installed; quieter and heats in winter |
| Fitted split running cost | £30–£70 per summer | Roughly 7–20p an hour |
| Crossover | ~15–25 summers | On running cost alone, ignoring comfort and heating |
Figures match our portable air conditioning guide and running cost data.
Portable vs fitted calculator FAQs
For occasional cooling, a rented flat, or where no external unit is allowed, they are the only realistic option. For a room you will cool every summer for years, a fitted split is quieter, cools properly and costs far less to run.
They draw close to full power most of the time, and the exhaust hose lets warm air back in around the window seal. A fitted split modulates down once the room is at temperature.
Normally not — nothing is fixed and nothing is drilled. Anything with an external condenser needs the landlord’s consent, and in a flat usually the freeholder’s too.
Some claim to, but poorly and expensively. For heating and cooling from one unit, a reversible split is the system that actually does it.
Related cost guides
- Portable AC guide — when a portable is the right answer
- Fitted split costs — the alternative priced properly
- Running costs — per hour and per summer
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