Digital Electronic 1000W MH/HPS Systems...

Okay. I'm in the market for a 1000W interchangeable system with a digital electronic ballast, and I'm just trying to get a little bit of information from people who may know a little more about them. I'm leaning towards a Lumatek system, but haven't ruled out other manufacturers.

Number one concern: I won't be buying an air-cooled hood with it because I'd like to try using an open 4'x4' umbrella reflector...so what can I expect in terms of heat? I know that the ballast will stay cooler, being digital with a built-in cooling fan, but I've also heard that the digital ballasts cause the bulbs to actually burn brighter. Does this, in essence, put off more heat created by the bulb itself?

The room is 6'x6', and 8' tall. Ventilation has always been focused more around odor control, as opposed to heat control, because a 6" inline air-cooled reflector is what I've been using in the past. Without using that, how hot can I expect the room to get? My exhaust is a 6" Fantech (around 250CFM, I think) hooked up to a homemade carbon filter, and vented directly outside. I was using an EcoPlus blower for intake, but can't use it anymore due to recurring malfunctions...and lack of money to replace it. (Dumping all extra spending cash into the new lighting system.) So, really, all I'll be using to deliver fresh air will be a window that's opened periodically, and several oscillating fans scattered throughout the room.

Is this going to get too hot? Any advice would be most appreciated.