Windows: open or closed during a heatwave?

Jul 18, 2022
The heat has prompted the UK's first red warning for extreme heat from the Met Office. Britons are being urged to stay inside during the hottest points of the day but what is the best way to keep cool in your property?
WINDOWS – OPEN OR CLOSED?
It may seem wise to open up the windows in your house to let a breeze through your home. But it may be better to have them shut, at least while they’re in direct sunlight.
It might seem counterintuitive, but if the air outside is hotter than the air in your home, keeping your windows closed could help your home stay a little cooler.
However, at night time, if it's slightly cooler, it may be best to have your windows open helping cool the room and to provide needed air circulation.
An indoor thermometer can help you determine whether your home is cooler or warmer than the temperature outside.
CURTAINS – OPEN OR CLOSED?
Much of the sunlight that enters your property through the windows turns into heat. Close curtains and blinds on rooms that face the sun to keep indoor spaces cooler (remembering it may be cooler outdoors than indoors). Keep them closed, at least during the hottest times of the day.
Shade or cover windows exposed to direct sunlight.
In future, you may want to think about blackout curtains to keep windows covered and block the sunlight out completely. External shutters or shades are very effective, while internal blinds or curtains are less effective but cheaper and easier to install. Simple changes to your property, such as using foil on windows could make a big difference.
TIPS FOR COPING IN HOT WEATHER
UK Health Security Agency resource to protect yourself and others: 'Beat the Heat: Keep cool at home checklist' which is available on the Heatwave plan for England page.
Image: Property in Elmwood Rd, Grove Park, Chiswick, W4. Let and managed by Harpers Of Chiswick.
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