Exhaust fan flapping in the wind

[bigtiller]

The wind blows here in the wide open country and when speed and direction is just right, the hinged door on the exhaust fan in the bathroom flaps up/down constantly and can be heard throughout the house. When it is not banging like a kids drum set, I don't know if it is closed or if it is being sucked wide open.

Is there a way this never-ending pounding can stop?

 

[CobyRupert]

..... when speed and direction is just right.....

Might take just the slightest change, like a 1-1/2" shroud/lip on one side or another to make all the difference.

 

[dave1949]

I've had that too. It has gone away after 5 years or so. Probably because the hinges aren't as free as they used to be?

One friend suggested double-sided magnets, like the flexible refrigerator magnets. Cut a small piece that is strong enough to resist wind flapping but small enough for the fan to overpower. I never tried it.

 

[zzvyb6]

Its probably flapping because there are pressure surges into the house. Figure out where the air is coming in and seal it. Then the flap won't have to open to release the pressure.

 

[ray66v]

If you have access to the exhaust piping, add: 4" Back Draft Damper | eBay to the pipe, as close to the fan as easily possible.

Not only will it stop the noise, because the stop in these is rubber so it is pretty quiet, it will stop 98% of your heat loss. Which, if all you have is the factory flapper, is more than a little bit. Not to mention the wind that is blowing in.

These are good quality, I have installed several of them. 4" is the most common. 6" is found on large units. Other sizes are available.

You cut the pipe, slip it in, and tape it up, with aluminum foil tape. (Not included, see Home Depot, heating and cooling department).

 

[bigtiller]

Can that back draft damper be installed from the interior or does someone have to crawl into the attic?

Dave,,, I was really hoping for mine to fix it's self also, but it has been about 15 now so,,, I may have to do something about it.

 

[ray66v]

No, it has to be put in line exhausting the fan. You only have access to that, from the attic, or area above the fan.

You can put it anywhere in the line, but the closer to the fan you get it, the better. That way, there is no chance of moisture freezing on it.

 

[oosik]

A small piece of very thin sticky back foam tape. On the back of the flap so that the flap closes on the tape. I know - about 2X/year mine will slam a couple times during a wind storm. Always at night - its enough to wake the dead and scare the b-jesus out of a chunk of railroad iron.

 

[leveled]

we use to install the metal vents before and now we use Vinyl. I like the draft dampener idea i will use this. one more point to make is to use insulated duct work, this will help to stop the condensing and ceiling stains that are so common in the colder areas.

 

[dave1949]

I put a backdraft damper in my 10" range hood pipe after giving up on the supplied damper. It's the vertical style with two half-circles on a shared shaft. The fan pushes them open and gravity closes them. Works well. I installed it in the fake cabinet above the range hood, easy to get at for maintenance but haven't to do anything yet in six years.

I sloped my vent piping in the attic down toward the exit so condensation has a chance to drain. In really cold weather the flap on the vent will get frozen/frosted shut. The fan will usually melt it and push it open but now and then I have to do it manually from outside.

The bathroom vents don't have a backdraft damper so there is always a little interior air drifting out through those for sure. Our house is very tight, so I don't worry too much about that.