Hello everyone!
I own a house built around 1960 and it has these ventilation boxes on the wall. A larger one in the living room, which is wired into the mains and blows fresh air into the house (see 1st pic below). And then 3 smaller units in the bedrooms that are mounted higher up and don't have any wires or switches (see 2nd pic).
I assume that back in the day, they were just an alternative to opening a window and allowing fresh air in?
Could I simply remove them and place a ventilation grill over them? Does anyone know why the smaller bedroom units have no visible wires or switches? How would they work?
Thanks in advance!