??????

So i was wondering...i just finished my room and covering it in mylar 4mm thick. Im goiing to be growing in a space thats almost 4 feet deep and juast undeer 6 feet high and about 3 and half feet wide..im going to use a 600 watt hps aircooled and was going to get an 8 inch fan and what i was gong to do was let the coll air blow into the room instead of out of the box and also have another vent with a fan blowing in cool air and there will also be a a ossilating fan in the room as well!! what do u think, think its ok to do that with the light exhaust??