Portable vs split air conditioning: which should you buy?
This is the first fork in the road for anyone buying AC in the UK, and it's mostly decided by two things: do you own the property, and how often will you actually use it?
The 60-second answer
- Renting, or cooling for a few heatwave weeks a year? Buy a portable. £300–£600, arrives in a box, vents out a window, comes with you when you move.
- Own your home and want reliable comfort every summer? A split system is the better machine in almost every way that matters — quieter, roughly a third of the running cost per unit of cooling, far more effective, and it heats in winter. The catch is a £1,500–£3,500 professional installation.
Side by side
| Portable | Wall-mounted split | |
|---|---|---|
| Upfront cost | £300–£600 | £1,500–£3,500 installed |
| Installation | None — window vent kit | F-Gas certified engineer, half a day to a day |
| Running cost | ~25–35p/hour | ~10–50p/hour, far more cooling per penny |
| Noise | Noticeable — the whole machine is in your room (typically 50–65 dB) | Quiet — compressor lives outside (indoor unit ~19–30 dB) |
| Effectiveness | OK for small rooms up to ~20 m² | Handles any room when sized correctly |
| Winter heating | Rarely | Yes — most are reversible heat pumps |
| Lifespan | 5–10 years | 10–15 years with servicing |
| Renters | Ideal | Needs landlord/freeholder consent |
Why portables lose on efficiency
A portable unit sits entirely inside the room it's cooling, so the heat it extracts has to be pushed out through a flexible hose — and the hose itself radiates heat back into the room. Worse, single-hose units create negative pressure that pulls warm air in from the rest of the house. They work, but they're fighting themselves. A split system rejects heat through the outdoor unit, which is why the same electricity buys you two to three times the cooling.
The cases where a portable is still right
Don't let the efficiency argument push you into a split you don't need. A portable genuinely wins when you rent (no consent battles, no lost deposit), when you'd only run it during the two or three hot weeks of a typical British summer, when you want to move it between bedroom and office, or when the room is small and the budget is fixed. See our current portable picks.
The cases where paying for a split pays back
If you work from home, a split earns its keep twice: comfortable summer productivity plus cheap single-room heating in winter that undercuts plug-in heaters. If anyone in the house sleeps badly in heat, the near-silent indoor unit matters more than any spec sheet. And installed AC adds a feature more UK buyers now actively look for as summers trend hotter. Get free installation quotes to see real numbers for your home.
Not sure what capacity you need either way? The sizing calculator gives you the right kW/BTU figure in 30 seconds — it matters just as much for portables as splits.