12" fan, 10" ducting. Will this work?

[redclayguerilla]

I have 10" insulated flex ducting running from the basement to the attic (roughly 20' run with (1) 90 degree turn coming out of the grow room). My setup is a 5'wide x 5'long x 8'tall room (with 2 vertical 1000w bulbs hanging vertically) adjacent to my veg room which contains a 8-light T5 and a couple of 4' 2-light T12s. My veg room has a 14" x 14" grated vent with a 3m filter that acts as a passive intake for the veg room while I also have passive intake vents from the veg room into the flower room.

With this said, would it be beneficial to use a 12" inline fan in the attic even though I have 10" ducting? 10" ducting is the largest diameter ducting I can possibly run.

Thoughts/suggestions?

I had planned on a 12" fan given i can install a variac to limit the fan's RPMs but maintain sufficient airflow.

Any input would be greatly appreciated.

 

[corky1968]

Maybe this will help you.

Place your fan at the big end and your all set to go.

http://www.homedepot.com/p/12-in-to-10-in-Round-Reducer-R12X10/100156649

 

[Ez Rider]

I have 10" insulated flex ducting running from the basement to the attic (roughly 20' run with (1) 90 degree turn coming out of the grow room). My setup is a 5'wide x 5'long x 8'tall room (with 2 vertical 1000w bulbs hanging vertically) adjacent to my veg room which contains a 8-light T5 and a couple of 4' 2-light T12s. My veg room has a 14" x 14" grated vent with a 3m filter that acts as a passive intake for the veg room while I also have passive intake vents from the veg room into the flower room.

With this said, would it be beneficial to use a 12" inline fan in the attic even though I have 10" ducting? 10" ducting is the largest diameter ducting I can possibly run.

Thoughts/suggestions?

I had planned on a 12" fan given i can install a variac to limit the fan's RPMs but maintain sufficient airflow.

Any input would be greatly appreciated.

The 10" duct will GREATLY reduce the cfm capacity and increase the noise of your 12" fan. Same size ducting is good, larger ducting is best. That being said, the 12" may still pull enough air to cool your space, but you're liable to overheat your fan. I'll bet an 8"maxfan will do your exhaust just fine, and will run nice and quiet on 10" duct. You also need to think about a powered intake with the amount of air you're exhausting. Maybe a 6"maxfan for intake?

 

[redclayguerilla]

Thanks Corky. Yeah, I know the adapters but was concerned the 12" to 10" adaptation would cause additional noise or cause some other issues.

Thanks again Corky!

 

[redclayguerilla]

Thank you EZ! I will into the 8" fans! I didn't think of the inverse: 8" fan on 10" ducting. That is food for thought!

 

[corky1968]

Thanks Corky. Yeah, I know the adapters but was concerned the 12" to 10" adaptation would cause additional noise or cause some other issues.

Thanks again Corky!

Make sure you place some type of vibration sound absorber anywhere the fan is hooked up.

I made a charcoal filter once and hooked it up and it made lots of vibration sounds because
of the fan unit. So I took a brand new thick towel and placed the towel around the pipe where
the fan was attached and then tied it back up. The more cushion, the less it will make noise.

The vibration noises basically disappeared.

 

[redclayguerilla]

I'll have to use that trick! Thank you!

 

[Ez Rider]

Thank you EZ! I will into the 8" fans! I didn't think of the inverse: 8" fan on 10" ducting. That is food for thought!

I run all my 6" fans on 8" duct...it work's awesome. Don't forget a powered intake. You'll need it running 2K in a 5x5 room.

 

[redclayguerilla]

I certainly will. Thank you!

 

[Granger2]

Replacing your flex duct with straight metal duct will give you much better air flow, and less noise. It's cheap too. I'm pretty sure that you can order it at Lowe's and HD. It is found elsewhere on the interwebs. Good luck. -granger

 

[redclayguerilla]

Thank you Granger!