Where does the air replacing all this exhausted air come in at?
Is this a belt drive centrifugal fan?
So, I decided to install powerful inline fan in my attic capable of moving close to 3000 CFM and do air exchange every 4-6 minutes. This will be my whole house fan solution for the 2-nd floor only.
I will install main trunk and then branch off to each individual bedroom/bathroom on a second floor. I have to use silencers because fan is definitely loud (seems like close to 70 db) and in addition to fan noise I would have to address aerodynamic noise coming from moving air @ pretty decent velocity through the ductwork.
The immediate problem is that the largest available silencer off the shelf is only 12" and my fan requires 16" so I can't install it without further restricting air flow through both inlet and exhaust side of it.
Secondly, I am torn apart what material/pipe to use as 16" galvanized pipe in 26 gauge is definitely not cheap and in addition I would have to spend extra time and money to further insulate it to reduce aerodynamic noise from air movement.
Therefore I was thinking about insulated flexible pipe (very cheap and easy to install) but this one has its own issues as there are a lot of spirals/ridges inside it and in order to avoid potential problems I would have to increase its diameter from 16" to 18" or even 20" to reduce air velocity.
So, what do I do? Any suggestions from Pro's?
Where does the air replacing all this exhausted air come in at?
Is this a belt drive centrifugal fan?
The air comes from open windows and it is large inline fan, like Fantech FKD series which I believe is direct drive
silencers only reduce sound of air velocity at terminals. not the sound of the fan if you were standing next to it or standing underneath it in your bedroom.
Hmm..exactly opposite to what I was told by Fantech tech support
So what do I do?
Live with the noise, or enter the 21st century and install an hvac system.
Large ducts, large diameter fan(s), slower blade speed.
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2 Tim 3:16-17
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well... 16" round flex will do what you want at a velocity of roughly 1100fpm for about 50-70 feet. they do make a blanket material you can use to reduce sound. or live with it. using flex alone will silence some of the sound of the fan at the terminals.
Tim, thanks for the suggestions. So forget silencers? I did mention that I am planning to oversize my ducts, what about using flex vs regular pipe? I really need to find a solution for the fan noise. If you guys are telling me that silencers will only help with aerodynamic noise and not fan noise, I am start questioning the whole installation idea.
silencers reduce the sound at the registers only.
did you start the fan with no ducts on it
70 db is no louder than the common TRANE condensing unit. Lol
Why not just buy one of these?http://www.airscapefans.com/products...se-Fans/Kohilo
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