With the UK experiencing high temperatures in May and June, many are looking for ways to keep their homes cool before the next heatwave. While portable air conditioners are tempting, there are low-cost, sustainable alternatives. Tom Greenhill, engineer and author of the Heatwave Toolkit website, warns that air conditioning benefits the privileged but harms the environment. He advises that even if you buy an air conditioner, passive measures like shading windows make it more effective.
External shading is key. Stuart Dantzic of the British Blind & Shutter Association notes that we wouldn't heat a building without insulating it, so why cool without shading? Shading fitted outside the glass can reject up to three times more solar heat than internal blinds. For the best results, cover skylights first, as they get direct sun most of the day.
Greenhill installed £80 Velux external awning blinds on his loft skylight, making it cooler than his neighbour's unshaded loft. He fitted them himself in half an hour. Velux offers manual anti-heat blinds from £110, promising up to 4°C cooler indoors, and electric shutters from £530, reducing heat by up to 5°C.
For renters or those on a budget, a £5 fitted sheet from Ikea can work. Bojana Bajzelj from Exeter used a king-size Bärglim sheet over her skylight, reducing kitchen temperature by 2-4°C while allowing daylight through. Repurposing old towels or curtains is also effective.
Large bifold or patio doors act as heat traps. A solar sail—a fabric stretch suspended between walls—can be a stylish solution. Greenhill suggests using stainless steel eyelets and carabiner clips for a DIY installation costing about £20. Companies like Kemp Sails offer custom options for those wanting to spend more.
