Existing ventilation is via a deep light well that has a screw open system with a pane of safety glass in roof to outside. I want to fit some sort of exhaust fan. I had thought to leave the existing system just open, and fit a double glazed unit with fan inserted to ceiling over the light well. Please advice me if this is sensible, cost effective, and if there is another economical way of dealing with this. Exiting system lets very cold air down into room in winter.
