Whether or not I go the full MVHR route, it still makes sense to duct away the smells and condensation from all the rooms that create it and have a single extraction fan. But how to turn it on?
Simple one-room/one-fan situation you run a feed from the light switch to the fan. If I do that here and common all the feeds then when you turn a light on in one of the rooms, the others light as well. Obvious, innit?!
I could have the feed powering a relay per room and the contacts of all the relays are commoned together to turn on the extractor but there's the aggro of housing the relays etc.
So.....just on the offchance, wondered if anyone knew of a gizmo that would do it all for me?