Well CO² really needs to reach about 1800 ppm and then you hold it there for hours if you can. Then you exhaust the room and start all over again. Sure a fan can move the air around even if your room is sealed. It's not like you have a lot of air pressure building up. The plants make oxygen as a byproduct of the chlorophyll process so that is not a problem.

You could use tank CO² and save the heat. Gas heaters put out carbon dioxide so be careful with that.
For dirt farming make sure you have drainage of the runoff water from the buckets.

3 rooms
1 - mother/clone room
2 - Veg room 18/6 or 24/7 your choice
3 - flower always 12/12

An old mobile home is better choice (if you have not purchased the container yet) only because of the insulation and easy construction on the inside. FYI.
Zandor Reviewed by Zandor on . Shipping container Hey all I own a 20 ft shipping container. The ones used on ships for cargo. I want to build a grow room out of it. Any suggestions, thoughts? I don't have to worry about hiding it from family but do worry about Da Man. Ciao Rating: 5