air tight flowering room, a few questions.

I'm finally getting around to setting up my flowering room and i wanna make it airtight, do i need to use a backdraft damper on my exhaust fan? I also, plan on mounting my ballasts out side the room on the wall. whats the best way to seal around where the cord comes into the room?

i dont use a damper and i use fix n foam to seal all holes...

damper is good to have anyway for the little bit they cost , if its cold and your fan is off you dont want that cold air going back into your room . silicon or foam , u could put a pipe though, and seal around it with silicon and use the pipe as alittle intake for the room . hope it helps

it does thanks!