out take fan running 24/7?

i have my room set up with a 4x4 aerotop aeroponics table 400 mh veg 600 hps flower huge can filter elicent exhaust fan with speed controler ..

Question?? do you put ur exhaust on a timmer or run it 24/7 i have a cold room so i am trying to get ideas as to how to increse the temp if i add a heater the heat will just get sucked out in seconds how does everyone have there exhaust set up .

I have read many threads but this simple question never seems to come up in conversation

in my prior grows i had the exhaust n intake fan running 24/7 just to make sure there was always good constant air flow in my control room. and i had my room set up in a cold cellar. also in the room i kept a heater that kicked in when ever the temp would drop to around 17. my heater had no problem keeping the room warm with the fans running 24/7.