Duct Delemma

[MTRUM75]

Hello, I’m putting together a small set up in my basement and do not know the best way to handle my duct dilemma. My original plan was to mount a Max Fan 8” (the only piece of equipment I own) in my attic and run 12 foot of 8” rigid duct through the back of a closet and straight into my grow room (Great Plan). I drilled my pilot hole and it’s not where I thought it was going to be. Now I need to use a 90 degree elbow and get through a 6” X 12-1/2” hole between joists.

The easiest solution would be to run the 8” duct to the floor in my closet then, use a 8” to 6” reducer -> 6” elbow -> 6” duct into the room then to the light.

My grow room is in the basement and is 91” X 137” X 85” tall and will be insulated. I plan on using a 600 watt A/C hood with a Can Filter 66 attached and using a speed controler on the fan. Grow table is 36” X 36”. The room will also house a small mother tent.

How would others get through the 6” X 12-1/2” hole? Is reducing to 6” something I don’t need to worry about since I will have plenty of fan?

Out Side Room

Out Side Room

Inside Room

Inside Room

Thank You.

 

[ItsAllOver]

I am only learning more about fans lately, but it seems to me like reducing is actually a big deal in killing the amount of air you fan moves, and although yours is big, you might not want to do that. If you only plan on using a 600w forever, maybe just go ahead. If you're ever going to upsize, you might regret cutting the big holes when you need to redo it all. What are your other options?

 

[Johnny Rotten]

Choking down to 6 in will definitely reduce your airflow, no doubt about it. If your fan is oversize for your application it would be fine as long as you lower the RPM's.

I'd make a square duct out of duct board and just use a collar at the end where your centrifugal can pull from with a bit of 8 in. flex. Don't know how handy you are or if you can get your hands on some.

I think 11x5 is close to 400 cfm, someone correct me if i'm wrong, i don't feel like getting the book out. You'd need 1 1/4 duct board for sure.

 

[McDanger]

Is this going to be an exhaust just for the light or is it for the whole room? If it is for the whole room you might be able to block off the entire cavity with just a vent cover in the ceiling of the room.

 

[MTRUM75]

Johnny Rotten, I am fairly handy and I need to get this right. I need some ideas to point me in the right direction.

McDanger, In the summer I plan on venting the light and room together. In the winter i most likely will not want to cool the light.

 

[MTRUM75]

As far as I can tell, going through the rectangle opening is my only option. Any additional help would be greatly appreciated.

Making something is defintly doable. Does any body know what duct board is?

Does any body know how the air flow would be effected if I take 8" duct and squeeze it into an oval to fit through my hole?

 

[ScrubNinja]

Here is a handy link for you.

The area of your 8" ducting is 50.3 sq in. The area of your rectangular hole is 75 sq in. That's equal to 9.8" round ducting. Get some 9.8" ducting and wedge it in, then use 8" reducers either end. I don't know what sizes are available so I guess they make a 10" duct? But yeah, that's what I'd do.