attic fan vibration

[@tinhhuynh2]

The noise is actually not of the fan. It's the vibration of the roofing around it. I "framed" the fan with 2x4's that fit the space between the rafter, and thickened the area around the opening with pieces of plywood, and it took care of the noise.

[@thebarcodeguy4420]

Every system has a "resonant" frequency. The one window down on the highway comment below is another example. By stiffening up the support you are helping to dampen the oscillations created by the "System". The cause of the oscillations is the mystery. Some ( below) say it's the lack of input air form the eaves vents. But you have solved it your way. Nicely done. In my opinion these fans are too big and too cheap to do their job with quality. I think the ventilation ( air flow) needed can be addressed by much smaller fans and possibly use 2 fans. This is obviously a wide spread issue. These fans are under designed on top of the fact that they are likely over kill.

[@alexbojsza734]

Can you show s picture of what you did

[@tinhhuynh2]

@@alexbojsza734 I will see if I can attach the pictures.

[@tinhhuynh2]

Sorry I can't paste the picture here, but what I did was adding pieces of woods around the fan to thicken the area, and that helped a lot. If I can find a way to post the pics I will!

[@matthewshelton1403]

Any updates on this? I too have this issue on a house we’re moving into next month. I’m concerned replacing it may not even do the trick. Maybe not enough ventilation into the attic so it’s causing the “one window down on freeway” syndrome.

[@stevenmorris204]

i had the roofer install a new unit and it was way better. However , if i could do it over maybe a smaller fan would be more quiet and sufficient. i am sure during the heat wave yours was running constantly as mine was. also a switch to over ride the power to the unit would also be good. i was forced to throw the circuit breaker at one point so I could sleep. i had 2 if these at my last house and they were fine , but smaller fans. i think 2 small fans is better than 1 large loud one.

[@matthewshelton1403]

@@stevenmorris204 there’s a possibility you don’t have adequate ventilation in the attic so instead it’s sucking air from the house through can lights, whole house fan, etc. They have wifi switches that you can turn on when you turn on your whole house fan so they work in conjunction.

[@thebarcodeguy4420]

@@matthewshelton1403 sure..always a possibility. When they renovated my house they installed all new soffets and over hangs with continuous holes all around the entire overhang of the house, but it's possible the installers didn't cut out the wood underneath. I would have to crawl down towards the edge of the attic to see. But yes that possible. The new fan is way more quiet , but still ventilation form the eve's is key. ( I agree)

[@johnwallacemcclure1143]

Couldn't hear your voice due to fan noise.

[@carminemartino8471]

Did you find a solution? I just installed a new one that pretty much looks the same and the vibration under it on BOTH floors of the home is aggravating. I can literally step 4 feet to the left or the right and I hear no sound or vibrations. Its like it vibrates through the walls.

[@stevenmorris204]

I had the roofer replace it . My wife says the new one is much more quiet , but with all my projects I have not climbed into my small attic yet to run it through some tests. My theory was that it is similar to when you open just one window in your car on the highway and it sets up a pounding resonant frequency. This is caused by the fan pushing air out with enough "supply" of air through the ridge vents possibly. I will let you know what I see when I try more tests. Note: the fan motor appears to be simply a 120V AC fan so the control is just a switch. Another solution could be to simply mount a much smaller quieter 120V AC fan into the housing. My feeling is the fan itself could be much smaller and still do the job. ( some active ventilation is way better than none at all) .

[@TK-setophaga]

those fans loosen the drywall on the floor below! there must be a better way