As the UK bakes in a record-breaking heatwave with temperatures reaching 40C, people are desperate for quick cooling solutions — we tested the most viral hacks to see if they really work.14:03, 24 Jun 2026It's social media's most talked-about cooling trick as Britain swelters in the grip of an extraordinary heatwave, and everyone's desperate to find out — does it genuinely work?‌With the UK bracing itself for potentially record-shattering temperatures of up to 40°C on Wednesday, 24 June, the Met Office has issued a rare red weather warning for vast swathes of the country.‌Amid the blistering heat, all anybody wants is a simple, quick and budget-friendly cooling solution that delivers real results.‌Step forward: tin foil. Or kitchen foil, or aluminium foil — call it what you like.This viral cooling trick, which involves taping foil across windows, has been dominating news headlines and spreading like wildfire on social media, with countless people vouching for how well it works, reports Wales Online.‌Another heatwave technique gaining traction is keeping windows shut rather than open during the hottest times of the day. While this might sound backwards and completely opposite to what anyone roasting in extreme temperatures would instinctively do, it's supposedly the heatwave solution we never knew we were missing.So, do these viral cooling methods genuinely deliver? Does tin foil really make a difference? Should we genuinely be keeping our windows closed during the day? Are there other typical heatwave blunders we're making? Let's investigate.Does tin foil actually work?Reach reporter Alex Evans actually put the 'tin foil' trick to the test — and the outcome took him by surprise. To put the heatwave's most talked-about cooling trick to the test, Alex stuck kitchen foil onto his windows overnight, preparing for the blistering heatwave due the following day.‌He tried the foil method in just one room of his house - the home office - and measured the temperature there against other parts of his property, discovering a "noticeable difference".According to Alex: "I walked into this room [the tin-foiled home office] at about midday and honestly, it was a noticeable difference. No lie, it's definitely the coolest part of the house.‌"For a little cross comparison, I put the thermostat in the unfoiled dining room downstairs and within 30 minutes it said 36C. I brought it back upstairs and put it in the office and it dropped instantly to 31C in here. It's definitely a bit cooler in there than it would have been without the foil."Top tip: It's important to note that experts have advised fixing the foil to the exterior of windows rather than the interior - to stop the glass from overheating.Most common errors during a heatwaveCountless people are unwittingly making these typical heatwave errors which can significantly worsen the temperatures indoors, and we've consulted experts to confirm these claims.‌WindowsAngus Struthers, Managing Director at heating and cooling specialists BOXT, explains: "Opening windows at the wrong time can actually make your home hotter. A lot of people throw every window open around them the second it gets hot, but if the air outside is warmer than the air inside, you're just letting more heat into the house. It's better to keep windows shut throughout the hottest part of the day and then open them up later in the evening once things cool down."FansSimply turning a fan on doesn't automatically bring down a room's temperature, according to Angus.‌The cooling expert adds: "Fans don't lower room temperature. They may make you feel cooler, but they don't actually lower the temperature of the room. If the room is already really hot and there's no airflow, a fan will just end up pushing warm air around and making you even more flustered. If you try using it alongside proper ventilation, like near an open window in the evening, it will help pull cooler air inside once temperatures outside start to drop."Household appliancesAnother significant mistake is running certain everyday household appliances during a heatwave, which actually increase a room's temperature, adding to already blistering conditions.Angus shares: "Everyday appliances quietly raise indoor temperatures. Obviously, we've all still got households to run during a heatwave, but appliances like tumble dryers, dishwashers, ovens and even gaming PCs generate extra heat, which can really add up, especially in smaller homes or flats.‌"It's worth avoiding these kinds of heat producing appliances during the hottest part of the afternoon, especially in smaller homes or flats where heat builds up quickly."Should windows be kept open or closed?Most of us have probably flung open a window at the first sign of soaring temperatures, but it turns out that could actually be making things worse.‌British Gas engineer Peter Knowles advises: "Keep windows closed during the day. It might feel contradictory, but during the daytime, it's best to keep windows closed to prevent warm air from entering your home. If you've got light-coloured curtains or blinds in heavier fabrics, they can also be effective at blocking heat, if they're kept closed."Jason Peterkin, CEO and founder of 247 Blinds, echoes the advise: "My top tip is to start by managing how much heat enters your home during the day. By closing your windows, which does sound slightly bizarre, and keeping your blinds drawn during the hottest part of the day, it helps prevent warm air and direct sunlight from raising a room's temperature."Angus from BOXT adds: "One of the cheapest ways to keep your home cool is by stopping the heat getting in to begin with. Simple things like keeping blinds closed during the hottest parts of the day, being smart with windows and cutting back on heat generation can make a real difference to how hot your home feels.‌"Shutting blinds to keep direct sunlight out and opening windows at the right times can stop homes from overheating. This'll reduce the strain and energy use of cooling systems that often get put on full blast once people decide they are too hot."Does keeping windows closed during the day actually help?As someone who regularly writes about heatwave hacks and cooling tips these days, I decided to put this straightforward cooling trick to the test myself.‌My work desk sits in my living room, which has an enormous floor-to-ceiling window. For the past two days — as well as today, when heatwave temperatures are reaching their peak — I've been closing my windows and drawing my blinds from the morning onwards, keeping them shut all day as the temperature soars.My trusty and beloved cooling tower fan has been by my side, quite frankly keeping me alive, while I experimented with this seemingly back-to-front cooling hack.While my brain may have initially screamed "this is insane", I'm pleased to report that my living room is cooler than ever before, and I have, in fact, successfully managed to stop the worst of the blistering heat from entering my home and holding me hostage.Article continues belowHowever, I wouldn't suggest this method to anyone who doesn't have a cooling fan blasting cold air right at them, or some other means of air circulation keeping them cool as a replacement for the windows.