breeding room in a shed in the uk

Right so here's what I'm thinking 16 ft x 12ft shed about 10ft high wood frame but mabey steel 100mm of insolation completely air tight apart from a inlet and exhausted fan with automatic valves that will shut if the room temperature starts to drop because it's pretty cold here i no what everyone thinking if you put something it a air tight box it will die the way to get around this the inlet fan will turn on once a hour to refresh the air in the winter skimmers will pull there air from outside as well.



What I was planning on having in the shed

8 2x2x2 tanks for breeding

4x4x1 frag tank

Then ro and salt water tanks

A work station for fragging and testing



Any input will be appreciated