Air conditioning in the UK: do you actually need it?

Air conditioning in the UK was once considered an extravagance reserved for offices and the very wealthy. But three consecutive summers with temperatures cracking 40°C — and a growing second-hand market for portable units — have forced millions of Britons to reconsider. The question isn’t whether summers are getting hotter. They clearly are. The question is whether a portable aircon unit is really the right answer.

How hot is too hot?

The UK Health Security Agency issues heat health alerts when temperatures exceed 25°C for three or more days consecutively. That threshold gets crossed more often now. In July 2022, parts of England hit 40.3°C — a national record. And while many homes in continental Europe were built with thick stone walls and shuttered windows designed to manage heat, the average British semi-detached simply wasn’t. Single-glazed windows, south-facing conservatories and poor roof insulation make UK homes surprisingly efficient at trapping heat once temperatures rise. So yes, for many people, the discomfort is real, not imagined.

What the portable units actually deliver

Portable air conditioners — the kind you wheel into a room and vent through a window or wall — have surged in popularity. Models from brands like Klarstein, De’Longhi and Meaco now dominate online searches each June. But they come with significant limitations. Most single-hose units exhaust hot air out through a duct while simultaneously pulling warm air in from elsewhere in your home to replace it, reducing efficiency considerably. Energy consumption is another concern — a typical 9,000 BTU portable unit running for eight hours a day could add roughly £1.50 to £2.50 to your daily electricity bill at current rates. That adds up fast across a heatwave. Still, dual-hose models perform meaningfully better, and some users report drops of 5°C to 8°C in bedroom temperatures overnight.

They’re not quiet either. Most units produce between 52 and 60 decibels — roughly comparable to a normal conversation — which some sleepers find intolerable.

The alternatives worth considering first

Before spending £300 to £700 on a portable unit, experts suggest a layered approach. Blackout blinds or external shutters can reduce solar heat gain by up to 70%. A good box fan — particularly one positioned to draw cooler night air in from outside — costs under £40 and uses a fraction of the electricity. Cooling the person rather than the room with a desk fan, damp towel or cooling pillow insert is often more effective than people expect. “The cheapest intervention is usually behavioural — closing windows and blinds during the day and opening them at night,” said a spokesperson for the Energy Saving Trust. “Most people do it the wrong way round.”

What’s the right call?

For most UK households, a portable aircon unit is a compromise: expensive to run, imperfect in performance, but genuinely useful during the handful of brutal nights that now arrive each summer. As climate projections point to hotter summers through the 2030s and beyond, the calculus may shift. Fixed split-system units — more efficient, quieter, and better performing — remain rare in UK homes but are slowly gaining ground. Whatever you decide this summer, the broader question of how British homes cope with heat isn’t going away.