During a heatwave, you actually reverse the usual ventilation routine: instead of opening the windows during the day, you ventilate mainly at night and in the early morning, when the outside air is coolest. During the day, you keep windows and curtains closed to keep heat out.
Why the timing of ventilation is so important
In warm weather, the outside air is often warmer during the day than the air already inside, especially in a well-insulated home. Opening windows during the day will therefore draw warm air inside, while at night and early in the morning you can use the cooler outside air to refresh the heat that has built up in the house.
How to ventilate smartly during a heatwave
- Keep windows, curtains and roller shutters closed during the day, especially on the side where the sun is shining.
- In the evening, as soon as it noticeably cools down outside, open windows on opposite sides of the house to create a through-draught (cross-ventilation).
- Ventilate at night and early in the morning for as long as is safe and practical, before the outside temperature rises again.
- Close windows and curtains again as soon as the outside air starts to become warmer than the air inside.
Consider safety when ventilating at night
Leaving ground-floor windows wide open at night may not be a pleasant idea for everyone. In that case, consider leaving windows slightly ajar, using a window that can be fixed in a safe, limited position, or ventilating mainly through windows on higher floors.
Help the airflow with a fan
A fan does not lower the temperature in the house, but it does help to spread the cooler night air that comes in through open windows more quickly around the room, and creates a cooling effect on your skin through air movement. This works best in combination with cross-ventilation: place the fan so that it blows the incoming outside air into the room. Our advice is to use an AirFlow AV25G pedestal fan or AirFlow TV26G tower fan for this: both are adjustable in height or direction, so you can direct the airflow precisely.
Frequently asked questions
Doesn't ventilating during the day still help a little?
In extreme heat, ventilating during the day often brings more heat inside than it cools. It is better to wait until the evening or night, when the outside air is cooler than the air inside.
Is a fan sufficient during a heatwave?
A fan moves air, but does not cool the air itself. Combined with smart ventilation at the coolest times of the day, a fan does help to spread that cooling effectively around the room.
View the full range of fans and cooling products from Dynter to keep your home comfortable during warm days.