The UK just broke its June temperature record. On 26 June 2026, Santon Downham in Suffolk hit 37.3°C, beating a mark that had stood since 1957. The Met Office had a Red Extreme Heat Warning in force for a third consecutive day, with 40°C in play across parts of the South East — close to the all-time UK high of 40.3°C set in Lincolnshire in July 2022.
Most British homes are built to hold heat in, not keep it out. That's brilliant in January and miserable in a heatwave. The good news is you can keep a house genuinely liveable through a spell like this without buying anything, and certainly without dropping a few hundred pounds on a portable air conditioner you'll use four days a year.
Here's how to do it, what actually works, and the cost maths on whether AC is ever worth it.
First, Understand How Heat Gets Into Your House
Three routes, in rough order of how much they matter:
The main sources of heat gain in a typical UK home:
- Sunlight through glass. South- and west-facing windows are the big one. Direct sun through a window dumps heat straight into the room and it doesn't leave easily. This is where most of the daytime gain comes from, and it's the easiest to stop.
- Warm air coming in. Once the outside temperature climbs above the inside temperature — usually late morning — every open window is letting heat in, not out.
- Heat your house makes itself. Ovens, hobs, tumble dryers, the back of the fridge, old halogen bulbs, a games console left on standby, even bodies. It adds up more than people think.
Get those three under control and you've done 80% of the work.
The Daytime Routine: Shut the House Down
The single most effective thing, and it's free: close your curtains and blinds on any window the sun is hitting, and keep them shut while the sun's on them. Light-coloured or blackout curtains work best. External shade — a blind, an awning, even a sheet pegged outside the glass — beats internal curtains, because it stops the heat before it gets through the window rather than trapping it inside.
Then close the windows in those rooms too, once the outside air is warmer than the inside. It feels counterintuitive on a hot day, but an open window in 35°C heat is an open door for that heat. The Red Cross and the Royal Meteorological Society both give the same advice: shut up the house during the day, open it up at night.
While you're at it:
Free daytime habits that make the biggest difference:
- Shut internal doors to rooms you're not using, especially sunny ones. Contain the heat where it lands instead of letting it spread.
- Turn off anything you're not using. TVs, laptops, chargers, the lot. Swap any remaining halogen or incandescent bulbs for LEDs — they run far cooler as well as cheaper.
- Cook cold, or cook late. The oven is one of the biggest heat sources in the house. A salad, or food cooked after dark, keeps the kitchen from becoming a radiator.
- Avoid the tumble dryer. Dry washing outside — it'll be bone dry in an hour in this weather anyway.
The Night Routine: Flush the Heat Out
When the outside temperature finally drops below the inside — usually mid-to-late evening — throw the house open. Windows on opposite sides of the house create a through-draught that pulls the day's heat out and drags cooler air in. If you've only got windows on one side, a fan in the window pointing outwards will push warm air out and help draw cooler air in elsewhere.
The catch this summer is that the heat hasn't always been leaving at night. The Met Office recorded widespread "tropical nights" during this heatwave — where the temperature never drops below 20°C — particularly in towns and cities, where brick and tarmac hold the day's heat. If that's you, the night flush helps less, and a fan earns its keep.
Make a Fan Work Like Air Conditioning
A fan doesn't cool the air. It moves it across your skin so sweat evaporates faster, which cools you. Two cheap tricks make it do more:
Two cheap ways to make a fan feel like AC:
- Damp cloth trick. Drape a wet towel or sheet over a clothes airer in front of the fan. As the fan blows through the damp fabric, the water evaporates and the air coming out the other side is genuinely cooler. It's the same physics as an air conditioner, for the price of a wet towel.
- Bowl of ice. A bowl or tray of ice (frozen water bottles work) in front of the fan does the same job for a sharper, shorter burst. Good for cooling a room down fast before bed.
For sleeping: a fan on a low setting, light cotton bedding, and a window open once the air outside has cooled. Stick your sheet in a bag in the freezer for an hour before bed if you're desperate — it won't last all night, but it helps you drop off.
So Do You Need a Portable Air Conditioner?
This is where The Home Concierge's usual question applies: before you spend, work out what you're actually buying. For another recent example of that approach, see our look at every bill that went up in April 2026.
A decent portable air conditioner costs £250–£450 to buy, and they're not cheap to run. A typical 7,000 BTU unit draws around 780W — so at roughly 27p per unit of electricity, that's about 20p an hour, or £1.60 for an eight-hour night.
A fan, by contrast, is almost free to run. A small 40–50W fan over the same eight-hour night costs around 8–12p. A big 100W pedestal fan still only comes to about 24p a night. Run the numbers and a portable AC costs ten to fifteen times more to run than a fan for the same night's sleep.
For the handful of genuinely extreme days the UK gets, a fan plus closed blinds plus a night flush keeps most bedrooms comfortable. If you have a medical reason to need reliable cooling, or someone in the house is genuinely vulnerable to heat, AC can be the right call — but for most people, most summers, it's a lot of money and running cost for a few nights' use.
Portable units have other downsides too: they're bulky to store eleven months of the year, they're loud, and the single-hose models have to vent out of a window through a kit that lets warm air leak back in around the gap. Spend £30 on a good fan and a couple of pounds on a window blind first, and see how far that gets you.
Don't Forget the People and Pets
Heat isn't just uncomfortable, it's dangerous. The UK Health Security Agency recorded an estimated 1,504 heat-related deaths in the summer of 2025, with older adults and people with health conditions most at risk. A red heat-health alert — the highest level — was in force across six English regions during this heatwave.
So while you're cooling the house: drink more water than you think you need, keep an eye on anyone elderly or unwell, and check on older neighbours and relatives, who often won't ask for help. Keep pets out of direct sun, leave water down in the shade, and never leave a dog in a parked car or conservatory.
The Short Version
Shut the house up during the day — curtains, blinds, windows, doors. Kill the heat your home makes itself. Open everything up at night to flush the warm air out. Put a fan to work with a damp towel or a bowl of ice. And before you spend a few hundred pounds on air conditioning, remember that a £30 fan does most of the job for a tenth of the running cost. Save the spend for the loft insulation that keeps this heat out next summer too.
You don't need to buy air conditioning to survive a UK heatwave. Close the house down during the day, flush it out at night, and put a £30 fan to work with a damp cloth or a bowl of ice. The people who stay comfortable are the ones who treat heat management as a routine, not a panic purchase.