Every figure checked against its source on 5 November 2026
Portable or fixed: which air conditioning should you buy?
Buy fixed if you own your home and want quiet, steady cooling for years. Buy portable if you rent, need something this week or cannot get consent. We fit fixed systems, so weigh our view accordingly, but a portable is the right call for a good many Croydon rooms, and we say so.
Ask for a quote
Name, number and postcode. We ring you to go through it.
How do the two compare?
| Portable | Fixed split | |
|---|---|---|
| Price, 12,000 BTU | £300 to £420 | About £1,900 fitted, plus £400 to £700 electrics |
| Compressor | In the room | Outside |
| Hot air leaves through | A hose in a partly open window | Refrigerant pipes to the outdoor unit |
| Consent | Rarely needed | Often needed |
| Floor space | Taken | None |
| Moves with you | Yes | No |
Prices are Checkatrade's, May 2026, with the fixed figure being its unit and labour prices added together. Larger portables run to about £450 at 14,000 BTU and £650 at 18,000. Source: Checkatrade cost guide.
Why does a portable lose on the hottest days?
Two reasons, both to do with the hose. The window has to stay partly open for it, so warm air comes in to replace what the hose pushes out. And the compressor, the part that makes the heat and the noise, is in the room you are trying to cool. A portable still helps, but on a top floor in a heatwave it often cannot hold the room down.
When is a portable the right buy?
- You rent, and the landlord will not agree to a fixed unit. A quarter of Croydon households rent privately.
- Your lease bans alterations, or the freeholder's charges for consent make a fixed unit poor value.
- The building is listed and you want relief this summer while the consent question is worked through.
- You need cooling for a handful of nights a year, not a season.
Source: ONS.
When does fixed pay you back?
When you are staying put and the room needs cooling often. A fixed unit is far quieter where you sleep, keeps the window shut on a noisy road, and if it is reversible it heats the room in winter at about a quarter of the cost of a plug-in heater, which offsets a good part of the higher price. See home air conditioning and air-to-air heat pumps.
Is there a middle option?
Yes: a monobloc unit, fixed to the wall and breathing through two grilles, with no outdoor box. It beats a portable on noise and performance and beats a split on how little it asks of the freeholder, but it is less efficient than a split and needs two holes in the wall. Our guide to units with no outdoor unit covers it.
What should you look for in a portable?
Check its output against the size table, bearing in mind a portable's rating does not compare directly with a split's. Dual-hose models cope better than single-hose ones. Read the sound level, because the compressor will be beside the bed. Plan the hose route and how you will seal the window gap. And note that new portables use lower-impact refrigerants, since GOV.UK says movable units on HFCs with a global warming potential above 150 are already banned. Source: GOV.UK guidance.
Questions people ask
What about a window unit?
They suit few British windows and any fixed change to a window needs thought in a flat or a conservation area. Checkatrade gives £300 to £1,200 for the unit plus £300 to £1,000 to fit.
Can a portable heat as well?
Some can, at the running cost of an electric heater. A reversible split is far cheaper to heat with; the figures are on the heat pump page.
Do you repair portables?
No. They are sealed retail appliances with little an engineer can do beyond what the manual says. We work on fixed systems.
Where these facts come from
Useful to have ready
With these we can give you a straight answer on the first call.
- Your postcode
- Flat, house or business premises
- Who owns the outside wall, if you lease or rent
- Which room, roughly how big, and which way the window faces
- Any conservation area or listing you know of
Ready to go ahead? Air conditioning in Croydon covers what we fit, what we look after and where we travel.
Ready to have it fitted?
Home air conditioning
Bedrooms, top-floor flats and loft rooms, with heating thrown in.
Air conditioning installation
A survey, a written price, then units, pipework and electrics fitted properly.
Air-to-air heat pumps
Cheaper warmth than a plug-in heater, and cooling from the same box.
More guides
How much does air conditioning cost?
Unit prices, labour, electrics, running costs and the extras flats add.
Planning permission for air conditioning: when you need it
The permitted development conditions, with Croydon's exceptions.
Can you have air conditioning without an outdoor unit?
Monobloc units explained: what they do well, where they fall short.
Air conditioning in a flat: who has to say yes?
Leases, freeholder charges, the one-unit-per-block rule and office conversions.
Is bedroom air conditioning worth the money?
The 26°C rule, what to try first, fixed or portable, and what a night costs.
Cooling a loft conversion: what actually works?
Why lofts overheat, what Part O misses, and where the units go.
Which size of air conditioner is right for the room?
A room size table, the adjustments that matter, and why bigger is not better.
Checking an installer on the F-gas register
Company certificates, personal qualifications, and who issues them.
Prefer a call back?
Leave your postcode and a line about the room, and we ring you. Or ring 020 8194 3009.