I just purchase a 4 season machine (air conditioner, Heater and dehumidifier all in one unit) and was wondering if I needed to exhaust the air or can I seal the room. I am asking because I seen in last months high times there was a huge warehouse where the air was never exhausted only circulated within the grow room just cooled and dehumidified. I am running 2 600 watt hps in my flowering area now with exhaust fan. I don't know why I really want to do it like since the unit will more then likely us more energy to run, besides security and better control of my total environment. any advice or comments welcome.