Yes, it is apparently. 7 months minimum to 1 year typically. Some people also use ozone machines instead of natural ventilation, but it's more common to just let it air out. Usually because they use UFFIs in building materials.
When I read it, there was no harem tag, the MC was adamantly against having a harem, I had found this on a list that included no harems, and the harem was basically forced onto the MC and he folded.
Dude, his whole point was to not get a fiancée, that's why he set such, in his opinion, high standards and didn't put too much thought into it. He didn't expect for it to backfire on him, because I'm guessing his list was a spur of the moment type of thing.
This aged poorly. ;-;
Man, I was reading hoping there wasn't going to be a harem, but sadly he ended up getting engaged to the Freya chick. I'm droppin this.