As the UK braces for another heatwave with temperatures potentially reaching the 30s, a common question resurfaces: should windows be kept open or closed? Seven specialists, including interior trends experts, heating engineers, doctors, and security advisors, have weighed in, and their verdict is unanimous.
Keep Windows Closed During the Day
Johanna Constantinou, interior trends specialist at Tapi Carpets and Floors, called leaving windows open during the hottest part of the day a major mistake. She explained that it is far more effective to keep windows, curtains, and blinds closed from late morning through to early evening to prevent warm air and direct sunlight from building up indoors. Once temperatures drop in the evening, windows should be opened strategically on opposite sides of the home to create cross-ventilation and let cooler air circulate naturally.
Martyn Bridges, Director of External Affairs at Worcester Bosch, supported this guidance, stating that during a heatwave, windows should generally be kept closed during the hottest parts of the day, especially in rooms exposed to direct sunlight. He also recommended keeping blinds or curtains closed to block out sunlight and reduce solar gain.
Nighttime Cooling and Sleep Tips
Dr Katie Tryon from Vitality Health advised drawing curtains and blinds during the day and keeping windows closed if in direct sunlight to stop hot air from entering. At night, when the air becomes cooler, leaving a window ajar can make it easier to sleep. Dr Punam Krishnan, working with Stannah, emphasised that physical preparation is as important as ventilation, suggesting methods such as cooling down the body before bed.
Victoria Robinson, product expert at Hillarys, agreed that drawing curtains and blinds during the day and keeping windows closed in direct sunlight helps keep bedrooms cool. She recommended opening windows on opposite sides of the property in the evening to create a cross-breeze, allowing air to circulate freely and cool rooms more quickly.
Expert Advice from University of Derby
Professor Chris Sansom, an authority in renewable energy storage at the University of Derby, advised a strategic approach: opening windows on opposite sides of the home creates a cooling cross-breeze. For even better results, he suggested opening windows at night and closing them during the day to trap cooler air inside. During daylight hours, opening windows on the shaded side of the home reduces the amount of heat and sunlight entering.
Security Concerns
Craig Andres from The Perspicacity Life warned that leaving windows wide open poses security risks. Simple mistakes such as leaving keys in locks or within reach of open windows, leaving doors unlocked, or windows ajar create easy opportunities for burglars. He noted that more than a quarter of summer burglaries are linked to these oversights.
Final Verdict
To boost sleep quality, maintain a comfortable temperature, or safeguard the home, the consensus is clear: avoid leaving windows open around the clock. Instead, keep them closed during the day and open them at night on opposite sides of the property to generate a cross-breeze for effective cooling.
