Sometimes you have to go in the grow room when its dark, that's why I bother otherwise I wouldn't ask. I wanted to be sure before I caused negative effects on my plants. Some people that use CO2 have to go in when dark since the CO2 levels aren't great for you while the lights on and you dont want the levels to drop during the light period.

The main reason I want this is I keep tools ect...in the same room and sometimes I need to get one which in difficult when its pitch black. The lights are on when im working most of the time.