Rolling shutters during a heatwave can make a real difference, but closing them completely all day is not always the best reflex.
The goal is to block direct sun while still managing air movement at the right hours.
When sunlight hits windows directly, the glass warms up and the room quickly gains heat. Rolling shutters create a barrier before the sun reaches the glass, which helps slow this effect.
For the best result, lower them before the hottest hours, especially on windows facing east in the morning, south at midday and west in the afternoon.
During the strongest sun, it is usually better to keep shutters almost fully closed. If your shutters allow small ventilation gaps, leave the slats slightly open so trapped hot air can escape.
In a dark room, a tiny opening at the bottom can also make the space more usable without letting in too much heat.
Do not wait until the room feels hot. Close the shutters early, then keep windows shut while the outside air is warmer than the indoor air.
Open windows and lift shutters in the early morning or late evening when outdoor air becomes cooler. Create a short cross-breeze if possible.
Bedrooms, kitchens and living rooms do not heat the same way. Focus first on the sunniest windows and the rooms used most often.
For a heatwave, close rolling shutters early and almost fully, then ventilate only during cooler hours. This simple timing often works better than leaving everything sealed all day.