I did a 4" to 3" reducer with 3" ducting and it worked fine, not optimally because of the backpressure that the reducer produced, but it worked. Thing is, I had to use a 130cfm fan to vent a 16 cuft box (2x2x4) because of that backpressure. With the size of area you want to use, I don't think a single 4" fan is going to cut it honestly as they don't really get any higher than 180cfm that I've seen.
redtails Reviewed by redtails on . Venting Using 2" PVC? My first post here. Love this site. Tons of great info. I've spent the past couple of weeks reading and searching to pick up knowledge. I see a lot of posts here that could be answered with a simple search. I believing in doing homework before asking questions! That said, here is my case. I'm looking for a little help setting up my grow room. Here is what I've got. Basement set up. Good climate control all year round. Ready access to electric and H20. Lockable and away from all utilities Rating: 5