My school is a typical 1780's Victorian pile in poor repair but unluckily listed. The walls are granite and 3ft thick and ceilings high with those thin tile panels bringing ceiling heights down. Windows are high up and don't let much air in. There are also old strip lights which have expensive replacement bulbs. Rooms are large and expensive to heat. Heating bill £1000 pcm in coldest months. Any ideas for energy efficiency/ updating into the current century? Knocking down not an option or new school!