Many specialists do not recommend completely closing blinds in high heat. Here’s why: when the roller shutter is completely lowered, an air space becomes trapped between the shutter and the window. Under the influence of the sun, this air heats up quickly. As it can no longer circulate, heat builds up and ends up being transmitted inside the home through the window. Conversely, half-open slats or slightly inclined shutters allow air to escape and limit this greenhouse effect.
To keep your home as cool as possible, here are the main recommendations:
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Do not completely close your roller shutters during the hottest hours.
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Leave the blades slightly open so that a little air can circulate.
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Open the shutter 5 to 10 centimeters at the bottom of the window.
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Keep windows closed during the day to prevent warm air from entering.
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Ventilate early in the morning or late in the evening, when the outside temperature is lower.
Beware of material damage
This heat buildup doesn’t just harm comfort. It can also damage installations. If the roller shutter is made of PVC and installed very close to the window, the heat can deform the slats. In the most extreme cases, the glass itself may crack or even shatter.
Leaving a space of a few centimeters under the shutter generally helps to avoid these problems while continuing to effectively protect the home from solar radiation.
This is why it is recommended not to lower the roller shutter completely. Leaving it ajar by five to ten centimeters allows air to circulate, without letting the sun’s rays penetrate.
