Living in a townhouse built in late 1800's. It was renovated by someone else 2 years ago. Two bathrooms have no operating windows, only glass block for reason that windows are in shower enclosure. Window size is 3' x 5'. Cannot stand the glass block and hate not having fresh air in that room. don't know how easy it is to remove the glass block and replace with what? Operating vinyl with translucent glass? These windows on 3rd and 4th floors-so the cost of scaffolding will add considerably to replacement cost. Any ideas?