Air cooled 1000w MH blockbuster?

I've been having issues keeping the heat up in my veg under a 1000 w MH. It pretty much stays high 60s. I have it vented but I put it on a timer to not vent so much and build up some heat. My question is how hot can I let my hood get? The metal top of the hood heats up real quick before the air temp in the room gets down, like probably to the point of being untouchable. I don't have an interval timer only a digital so I kinda set it to come on for about 30 min every 3 hours or so.

Speed controller will help to control your temp better by reducing fan speed allowing radiant heat from your lamp back into your room.



J