There's a definite difference. A lot depends on if it's a closet grow or a grow cab. A couple of years ago I had a small grow cab (12" x 24" x 42") and I did all CFL--I had 4 x 26w on the canopy, and 2 x 26w hanging down a little lower. I remember the temp difference was about 3 or 4 degrees during flowering, even with the fan on. So if you're average is in the low 80s during veg, you might be getting into a bad area during flowering unless you increase your ventilation.

Closet are so great because you've got added area for heat dissipation. If you're in a closet, having the door open for a while each day will make up most if not all the temp difference.