I'm renovating my bedroom and found that there's a hole in the wall beneath the wallpaper. It was plugged, but the stuff in it was old and crappy, so I took it out. Now I've got a 20x20cm (~7.9x7.9in) square hole in my wall that goes to the outside.
The simple solution would be to simply fill it with spray foam and be done with it, but I was wondering if maybe I could use it for additional ventilation. God knows it gets hot and stuffy in the summer. If I had an air conditioner, it'd be a perfect hole for the exhaust pipe, but I don't so...
Anyways, if I do keep it for ventilation, I'd also need to add some kind of door to it because I don't want more cold to come in the winter. I'd probably use a fan for the summer. I haven't seen anything like that though, nor do I know where to look. The local home improvement store employees were also at a loss.
Does anyone have any ideas?