Two venetian blinds or a fingerprint scanner - which would you choose?

*Edit: Since there are quite a few supporters of venetian blinds here. Do you actually also have additional roller shutters that you lower at night in terms of thermal insulation? Or more like: you have to choose the lesser of two evils, we prefer the benefits of heat insulation - of course, more heat is lost at night in our case than with a house with roller shutters.

I also did some research back then when building, and the statement was always that the additional thermal protection provided by roller shutters no longer plays a role with current triple-glazed windows.

Back then, when I was building, I also did some research, and the statement was always that the additional thermal insulation provided by roller shutters no longer plays a role with current triple-glazed windows.

Hmm, let's say your window has a U-value of 0.9. If I then lower a roller shutter in front of it, which might even be insulated on the inside (that’s supposed to exist nowadays), then I have 1) the air layer between the roller shutter and the window glass that provides some insulation, and 2) the insulated roller shutter itself.

The question is how much that actually matters? But since it gets coldest at night and the roller shutter is usually down at night, I do think you notice it?

Yes, you can definitely tell.

An absolutely scientific proof. Sorry, but I never believe that a plastic roller shutter contributes significantly to heat insulation.

Quick&Dirty... but everyone has the most powerful tool in front of them and can inform themselves.

The big landlords and energy companies claim exactly that.

Yes, you can definitely tell.

If you search just as quick & dirty for insulated glazing and thermal insulation glazing, a window with a U-value of 2.5 is compared to one with a U-value of 1.1 in the photo. Comparing apples and oranges.