I just put 4 of those 4' four bulb t5ho light fixtures in my garage from homedepot, 20k lumens each, 11' ceilings. its nice would not change a thing, had them wired on 2 switches so i can have 2 on 2 off or all 4 on.
they just did a episode on (ask this old house) about this same thing, they said do not under and circumstances vent out throught the sofit, they showed a house with the vent ran that way and the complete attic was full of mold!!!