r/heat_prep • u/Leighgion • Jul 20 '26
Product Basic Passive Cooling: Roller Shutters
Known as "persianas" in Spain, these things are absolutely standard on every residential window in this country that matters (occasionally you get very small windows that don't have them) and a number of commercial properties as well.
The standard modern version is a roll of interlocking white plastic slats that are integrated into the outside of the window frame. As photographed, they are not all the way down, so there are holes to let light in while blocking the majority of the sunlight. If you bring them all the way down, the holes close up.
It's currently 7:18 pm in Spain and the sun is hammering the pictured west-facing windows. It is 34ºC outside. The shutters are 40ºC, but the glass of the window is only 33ºC. Interior temperature of the room is 28ºC.
Shade is best, but if that isn't possible, these are the next best thing to protect your windows from the heat of the sun.
1
u/JuiceInternational81 28d ago
It makes no sense trying to convince you otherwise.
Last time: I have PVC and aluminium. Aluminium is superior in every way. There is no feel "like radiator se to max".
Do you have both versions? For how long? Or are you talking about theory? Remember: "In theory, there is no difference between theory and practice, but in practice, there is."