Fewer than 5% of UK homes have built-in air conditioning, a fact that leaves millions of households sweltering as summer temperatures climb. Unlike the United States, where air-con is considered essential, British properties were designed to trap heat during long winters and mild summers – not to release it. With the Met Office warning that heatwaves like the 2018 scorcher are now 30 times more likely to occur because of climate change, and projections suggesting such events could become a near-annual fixture by 2050, the need for affordable cooling solutions has never been more urgent.
The DIY approach: making your own air conditioner
You do not need to spend thousands of pounds on a split-system unit – the cheapest single-room installation starts at around £550 and can reach £2,100 – to make a noticeable difference. One of the most effective low-cost methods is to create your own air conditioning unit using items you probably already have at home.
Take a plastic bottle, fill it with water, and add a tablespoon of salt before placing it in the freezer. The salt lowers the freezing point of the water, producing ice that is significantly colder than ordinary ice. Once frozen, position the bottle in front of a fan. As the ice melts, the breeze from the fan picks up the cool air radiating from the surface of the ice, creating a refreshing, air-conditioner-like current that can lower the temperature of a stuffy room for pennies per hour.
If you do not have salt or a suitable bottle, a bowl filled with cold water placed directly in front of a fan works in a similar way. Alternatively, drape a wet towel over the front of the fan – the evaporative cooling effect will chill the air as it passes through the damp fabric. For larger spaces, hang a damp sheet by an open window. The outdoor breeze will be cooled as it filters through the moisture, drawing cooler air into the room. Spraying curtains or blinds with cold water creates a comparable effect, although this needs to be repeated as the fabric dries.
Dehumidifiers can also help. In the UK’s often humid climate, removing moisture from the air makes it feel cooler without actually lowering the temperature, and these units are generally cheaper to run than air conditioning.
Keeping the heat out and the airflow right
Preventing heat from entering your home in the first place is just as important as generating cool air. During the hottest part of the day, keep curtains and blinds closed – blackout varieties are most effective. Venetian blinds allow you to adjust the slats to control light while still blocking direct solar gain. An open window in the middle of a heatwave will simply let hot air pour in, defeating the purpose of any fan you have running.
Once temperatures drop in the evening, throw the windows open. Night air is considerably cooler and will circulate through the house, making it easier to sleep. If insects are a problem, consider investing in a net. Inside the home, keep doors to unused rooms shut during the day so that any available breeze concentrates in the spaces you are using. At night, leave bedroom doors open to allow cool air to travel freely.
If you have more than one fan, create a cross-breeze. Place one fan by a doorway blowing cool air into the room, and another in a window facing outward to pull hot air away. Position yourself between the two for the best effect. This constant flow of air mimics mechanical ventilation systems, which are increasingly used in modern, well-sealed buildings to extract heat and draw in fresh, cooler air.
Internal heat sources also need attention. Lightbulbs generate heat, so keep them switched off where possible – an added bonus for your energy bills. Similarly, electrical appliances radiate warmth even on standby, a phenomenon sometimes called “vampire power”. Unplug any device not in active use, including televisions, speakers and phone chargers. The same logic applies to cooking: an oven running at 300°F for 40 minutes will pump heat into your kitchen. Opt for cold meals, use a slow cooker, or grill outdoors if you can. If you must boil anything, keep a lid on the pan to contain the steam.
Steam from showers and baths is another culprit. Hot water creates a warm humidity that is hard to shift when it is already humid outside. Taking a lukewarm or cold shower not only feels refreshing but also avoids adding moisture to the air. Try to limit use of washing machines and dishwashers during the hottest hours, and be careful when opening their doors.
Bedding and plants: small changes that add up
Your choice of bedding can make a real difference on hot nights. Sateen sheets are more effective at wicking sweat than standard cotton and cost less than silk, making them a sensible swap when the mercury rises. Pillow inserts designed to stay cool – they do not need refrigeration – can also provide relief.
Houseplants offer a natural, low-cost way to cool your home. During warm weather, plants release excess water vapour from their leaves through a process called transpiration, which cools both the plant and the surrounding air. The best options for this purpose include rubber plants (Ficus Elastica), Chinese evergreens (Aglaonema), palms such as the Areca or Lady Palm, mother-in-law’s tongues (Sansevieria), and Ficus benjamina. Peace lilies, Boston ferns and aloe vera also help, and many of these species improve indoor air quality at the same time.
Beyond these steps, a few simple checks can prepare you for the next heatwave. Make sure you have enough supplies of food, water and any medication you need. Arrange extra support if necessary – for example, help with shopping if it is too hot to go out. Verify that your fridge and freezers are working properly, that any fans or air-conditioning units you own are in good order, and that windows and vents can be opened safely. Turn off your central heating. Keep a thermometer in a commonly used room, out of direct sunlight, so you can monitor the indoor temperature. And if all else fails, a cold flannel on your forehead should tide you over.