My DR is 4'x4' and 80'' tall.. I veg with a 1000w metal haylide and flower with my HP.. Its in a 6inch cool tube so i got a inline fan on that and a circulation fan going and their healthy as could be and its actualy fairly cool in there lol.. BUT the actual location of my grow room is very cool and dry.. Oh and i also have a DR60 wich i forget the dimensions but its very small i think 2x2x4.5 tall with a 400w batwing setup in there and never had any heat issues.. Dont know if that helps lol?