Finally got round to sorting drobe temps out.....for now. Gonna have to revise this in 2 weeks in flower. No other option but to reverse current system and place the filter in the grow section, and draw the air through and then vent out. Current system has the air venting into the room.
The problem is that I an too used to shite , cheap ass rented property, and have no experience with modern BER rating houses. I am basically creating heat with the current system and then venting the same heat back into the grow, with associated low humidity problem.