# Block off bathroom vent in winter?



## velvetfoot (Dec 21, 2017)

Upon investigating a malfunctioning bathroom fan, I noticed a bit of  incoming cold air .  This bathroom is on the second floor .  

There is no damper in the fan, which is, like, 12 years old.  Maybe it was removed by the previous owner.

I found a similar new old sock unit on ebay  for 35 bucks and hope to swap the guts out of the old one with the new, including the damper.

I read that for that vintage of damper, it is partially opened at neutral state for insulation on unit/fire code issue.

Besides, in my mind, in winter with house stack effect, there'd be more of a chance of heated air leaving the building envelope.  The damper seems to protect cold air from entering the house, not the other way.  Cold air wouldn't even be felt with he heated air leaving the house.

Anyway, I'm thinking of blocking it off during the winter.  It's pretty dry in the house.  Of course there's the stinky bathroom factor, which could make it a deal breaker for the wife, lol.

Any thoughts/ideas?  I've never heard of a two way damper.  I doubt I'd be able to reverse the damper.  Maybe attach a coin to the damper flap?


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## Sodbuster (Dec 21, 2017)

I wouldn't, I'd swap it for one with a damper, plus there are exterior dampered  louvered vent terminations you can install.


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## peakbagger (Dec 22, 2017)

You need one of these, http://www.houseneeds.com/exhaust-f...ion-fans/tamarack-back-draft-preventer-damper Most houses are negative compared to the outdoors especially with wood stoves in winter. Standard dampers usually leak, these reportedly do not. Of course you still have the problem that if you seal up  this air leak, if the house is negative its going to come in from somewhere else or you start to have issue with the stove not burning correctly and radon (if you are in area with underground radon. 

An added note, if you ever take a bathroom fan apart you will find that its a very cheap device, not very well built to keep the cold air from coming back in. 

Time to consider an air to air heat exchanger. It brings in outdoor air to balance the pressure difference between the outdoors and indoors. Super insulated homes seals up every air leak they can and then use an ex changer to carefully add air back in where you want to it to come in rather than the bathroom.


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## EatenByLimestone (Dec 22, 2017)

I wouldn't.  If there's a shower being used in there, you might find it hard to keep paint on the walls.


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## woodgeek (Dec 22, 2017)

I wouldn't sweat a slightly ajar new damper.....what are we talking about here....<1 in^2 free section?

Your house probably has several hundred square inches of free section leakage all over the place...if it is 'tight'..otherwise it is _thousands_...you just can't feel the drafts they pull in or see them.

You have already spent way too much time thinking about those few square inches....go find some others to eliminate...I guarantee they exist.


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## coutufr (Dec 22, 2017)

You can certainly make it better but aiming for perfection is a waist of time and money. When you close one hole it just makes more comming from the remaining holes. It is also necessary for getting rid of extra moisture and contaminants from inside the house. The best thing I did for my house was to change all the doors and windows. I also installed new ceiling fans in the bathroom and outside evacuation dampers that close themselves when not in use. Humidity is around 40% inside the house all winter, no condensation in the windows unless it gets around 0 F


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## velvetfoot (Dec 22, 2017)

Sodbuster said:


> I wouldn't, I'd swap it for one with a damper, plus there are exterior dampered  louvered vent terminations you can install.


You know, believe it or not, I have an exterior dampered vent!  So, I guess things aren't as bad as I thought!  Duh.


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## velvetfoot (Dec 30, 2017)

Got the new fan.   Could not put its damper in the old shell.  Gave up.  Put up everything else.  Works fine.  No trip to attic.   I'll call it a success.


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## EatenByLimestone (Dec 31, 2017)

Win!


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## velvetfoot (Dec 31, 2017)

There is a resonant vibration that pops up once in a while, so I'll have to address that.


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## EatenByLimestone (Dec 31, 2017)

Can you use a little piece of rubber to stop the noise?  I keep an old tire  tube around and cut off pieces for stuff like that.


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## velvetfoot (Dec 31, 2017)

Yeah.  Maybe caulk as well.  Have to disassemble and try to isolate.  Doing other stuff around house as well.  
Anyway, Happy New Year!


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## EatenByLimestone (Dec 31, 2017)

You too!  It's a basement cleaning day here.  I'm not really looking forward to leaving the house.  Lol


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