In and out air circulation?

This may be a silly question but I cant seem to find a definite answer. (an answer I can understand).

Does a bathroom exhaust fan let fresh air in while taking out air? My room is 5' wide by 10' long by 8' high. I currently am using a small 50cfl bathroom fan with a 3" line outside. I used this while cloning but now I know I will need to upgrade as the plants are getting to be a foot tall. I have 6 plants with a 400watt HPS light.

I am not sure if I need intake holes into the room or if a higher output fan would be good enough.

So far the plants seem to be very healthy and growing at a nice pace.

Welcome Ottobus. A very basic answer to your question is 'yes'... you need inflow air to replace your outflow air. Depending on your particular situation, it could be as simple as installing a vent plate towards the bottom of an opposite wall if there is 'fresh' air on the opposite side of that wall. Basically, for every cubic foot of air exhausted, you should provide a cubic foot of fresh air into the room. If you're concerned about light leakage, you'll need to run a duct up ( or over, or down) and away. Hope this helps.

Thanks man. Great response. I have been a little paranoid (ha ha) on not giving the little darlings enough to breath. I have been so worried on how to keep them healthy with fertilizer, and such that I forgot to feed them AIR.

Been smoking the NATURE SMOKE for over 20 years and never really thought about the love and care that goes into producing it.