From personal experience I know that Scandinavians rarely use or even have curtains. I was going to tell you so, but first I did a GIS for “Scandinavia curtains” and found pages over pages of Scandinavian curtains offered for purchase.
That puzzled me slightly.
My next GIS was “Scandinavia windows”, which resulted in shittons of pictures of nekkid windows without coverings.
There appears to be a surplus of better than average looking Scandinavian window-treatments.
Scandinavians rarely have curtains on their windows. Those that do seldomly use them. (Same as the northern Dutch and very northern Germans.)
Within its limitation my research would lead to the obvious preliminary conclusion:
Scandinavians have good taste in window coverings, but feel no need for them.
Scandinavians sell all their curtains instead of using them to shut themselves off from the world.