Sorry bigsby, it is more conjecture on my part, never tried a 2" exhaust. But I can say that I have a hard enough time maintaining temps on my 400w cab... small ducting, small fan and several bends in the duct make things more difficult.

If you do some calculations, the area of the duct (area of 6, 4 & 2 in. circles) and volume differences (cylinders) reducing from a 6" to 4" and 4" to 2" are pretty significant. You'll have to worry about the fan noise AND the whistling, pressurized exhaust air, and maintaining good temps might also be a problem... There's probably a good reason why 2" ducting isn't produced.

A lot depends on the temps in the basement too. In order to cool that 400w, you'll need a strong fan or cool intake temps (this would most likely require a heater for when the lights are off).

That's why I'm suggesting to keep all the exhaust in the basement if possible. Use a carbon filter in the growroom, and one in the basement room (or some other odor neutralizer). Then there are some instructions online for silencing inline fans, it think you'll be set.
bigtopsfinn Reviewed by bigtopsfinn 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