As temperatures rise, staying cool indoors can be a challenge in the UK, where air conditioning is far from common.
While many turn to electric fans, others may wonder whether opening windows actually helps or makes things worse.
Now, UK housebuilder and Ty Eco owner John Small has shared his advice on how to keep your home “cool as a cave” this summer.
Should you open or close your windows during a heatwave?
Ty Eco founder John follows the PassiveHaus UK principles, which help new-build and re-fitted homes beat the heat.
What is a heatwave?
He said: “If it’s cooler inside than outside, you should keep your windows closed.”
John added that while it can be tempting to open your windows during a heatwave, you’re only bringing the warm heat inside, making your home hotter.
He explained the science behind his advice: “Heat enters our house in two ways: solar radiation from the sun, and hot air.
“We want to limit both, by closing the windows and curtains – but, if it reaches a point where the temperature inside the house is equal to that outside, then you should open the windows, keeping the curtains closed.”
If you want to open the windows, there’s a specific time you can try it.
John explains that you can open your windows to keep cool in the late evening through to early in the morning until 9am.
He advises keeping windows closed outside of this period.
John added: “For those really feeling the heat, it may be that your home is actually warmer inside than out, in which case, I would advise you to reverse the advice, but be wary, how it feels, and the actual temperature is deceiving, so always use a cheap temperature probe.”
British Red Cross said: “Opening a window doesn't always mean you're cooling your home. In fact, if the air outside is warmer you could risk making it worse.
How to cope with hot weather
“During the hottest parts of the day, it's best to close windows to keep the warmer air out. Check the forecast to gauge when temperatures are starting to rise.
“Wait until the cooler times of the day to open windows. When they are open, you can creating a breeze in your home by opening different windows to help air to circulate.”
If you’re still struggling to keep your house cool, John said you could use privacy film.
Recommended reading:
- What time should I shut my windows to stop the heat? How to keep cool in summer
- Can you use a watering can during a hosepipe ban? Temperatures set to soar
- Do you suffer from swollen feet in the summer? 6 ways to prevent heat oedema
This is used in hotter climates around the world and increases your windows’ ability to bounce away heat, and will lower your home's internal temperature.
A reflective film blocks the radiation heat from the sun and offers extra privacy.
He said the heat film is also designed to allow the same amount of natural summer light into your home.
Do you already follow this advice on keeping windows shut in hot weather? Let us know in the comments.
