Europe is in the grip of a record-breaking heatwave. To help stay cool, people in France have been turning to an unusual solution – chalk. Here's the science behind the trend.
Do you put it on the inside or outside? Seems like outside would be better because heat it radiates to the outside would go directly to the air, and heat it radiates to the inside would have to go through the glass first.
Yes outside is better. One can also buy transparent heat protection foils which can be glued to the window, and with these it is actually important to put them outside, otherwise the window can become too hot, and become damaged. (In the case of the white paint, physics is a bit different since more of the light is reflected directly, but outside is still better, as with all kinds of blinds.)
Do you put it on the inside or outside? Seems like outside would be better because heat it radiates to the outside would go directly to the air, and heat it radiates to the inside would have to go through the glass first.
Yes outside is better. One can also buy transparent heat protection foils which can be glued to the window, and with these it is actually important to put them outside, otherwise the window can become too hot, and become damaged. (In the case of the white paint, physics is a bit different since more of the light is reflected directly, but outside is still better, as with all kinds of blinds.)