Hi all, We're at the stage with our building control/timber frame design drawings where we could really do with an MVHR design. We're building a large house with a basement and a room above a double garage. total internal floor area is approx. 450m2 (including the double garage, so about 405m2 habitable space). I have roughly calculated the volume to be 1150m3 (we have a high vaulted entrance hall, and the room above the garage is also vaulted and our basement has 2.9m high ceilings) and us