Cold air thru bathroom fan

[treewoman]

I had a thru the wall Panasonic fan installed in my bathroom back in Sept, since there was no ventilation and I didn't want the mildew problems that the previous owners had. ( just bought the house in May, and the bathroom closet had a lot of mildew.) Now with winter here, when it's cold and windy, I get a draft from the fan. If it's REALLY windy I can see the flap opening to the outdoors! I really like the fan, it's efficent and quiet (which is why I chose the Pansonic) but this has me worried, with heating bills as high as they are. And...it's a tad drafty in the shower if I run the fan while showering! Any suggestions?

[Toolpusher]

Not sure what the thru the wall fan looks like,
But, can you seal it from the outside ?

I would think the flap would close if the air from outside hits against it. And open as the inside air gets pushed out.

[pcscott]

Check the flap for a missing spring.

[grndsm]

Something to think about, do you really need to use this fan in the winter? The inside air tends to be so much dryer, that if you simply leave the bathroom door open after you are done, the moisture in the bathroom should evaporate rather quickly. I would consider putting this fan on vacation (by covering it form the outside) until spring.

An added benefit is that you will get more moisture in the rest of house, reducing or even eliminating the need for a humidifier.

I have made a similar observation in my house (where we just added a fan to a totally closed-in bathroom) and now I am fighting with my wife to keep her from using our fan in the winter months.

[treewoman]

Originally posted by Toolpusher
Not sure what the thru the wall fan looks like,
But, can you seal it from the outside ?

I would think the flap would close if the air from outside hits against it. And open as the inside air gets pushed out.

Yes, the idea is that the flap opens when I turn on the fan and closes when outside air hits it. However, when it's really windy, I have seen it open and can see "sky". I could seal it from inside or outside, but was trying to keep my bathroom dry. But as another person mentioned, that's probably not necessary in winter! Regardless, I will contact Panasonic about this. Thanks for your input!

[treewoman]

Originally posted by pcscott
Check the flap for a missing spring.

OK, I will check that! Thanks!

[treewoman]

Originally posted by grndsm
Something to think about, do you really need to use this fan in the winter? The inside air tends to be so much dryer, that if you simply leave the bathroom door open after you are done, the moisture in the bathroom should evaporate rather quickly. I would consider putting this fan on vacation (by covering it form the outside) until spring.

An added benefit is that you will get more moisture in the rest of house, reducing or even eliminating the need for a humidifier.

I have made a similar observation in my house (where we just added a fan to a totally closed-in bathroom) and now I am fighting with my wife to keep her from using our fan in the winter months.

Maybe you are right, maybe I don't need the fan in the winter! However, I can still feel a draft from it on cold or windy days that is allowing a lot of cold air into my house. If you had a door or window leaking like that, you would certainly do something about it, right? Maybe at this time of year I am not so concerned about the moisture retained in the bathroom as I am about the cold air leaking in. Do you think I should just throw a blanket of insulation over it?

[propmanage]

Problem could be a very short straight flex duct and if the wind hits just right it will pop open the damper and you could feel the cold air draft in the room. The only short solution with out taking a lot of time and changing things around would be to pull the cover during the winter months and insert some thin solid insulation then remove for summer. If you really want to get to the bottom of this issue you would need to check the balance of the outside air with the bathroom air and see if the room is getting more of a draft/pressure change then it should. If the room is at the top of a stair case and you have a good size space under the door that could be part of the problem like a chimney effect. Do you have an attic door near this bathroom?

[atphvac]

I don't know how yours is installed but typically the vent outlet on the fan is pointing upwards and then 90's through the wall to the wall cap. The best fix I found was using a butterfly damper from Fantech which you would have installed inline just before the 90 goes through to outside. They seal extremely well. You have to make sure your fan will push the flaps open but with such a short run to outside it shouldn't be a problem.

[smokin68]

[And...it's a tad drafty in the shower if I run the fan while showering! Any suggestions? [/B][/QUOTE]


Don't run the fan.

Seriously, maybe the fans too large for your room.

[tinknocker service tech]

replace the vent cap with a spring loaded one this way the flapper will only open when the fan is on.

if it is flapping with the wind chances are it is a gravity flapper

[treewoman]

Thanks, that makes sense! I appreciate everyone's comments and will check out all options. The fan is a straight shot from the bathroom to the outdoor, thru 6 inches of wall, so there is no 90 degree turn or anything. I am afraid to not use it, don't want moisture or mildew problems, but yet it seems strange in these days of insulation to have a thin piece of metal holding back the cold from my house. I do really like the Panasonic fans tho, don't think you can buy anything more powerful or more quiet! Most people are not familiar with them because they are not sold thru stores. They are so quiet that it is really easy to leave it on all day or night and not realize it ....that could be a downside, but I hate a noisy fan!

[perel]

Originally posted by treewoman
They are so quiet that it is really easy to leave it on all day or night and not realize it ....that could be a downside, but I hate a noisy fan!

Put the fan on a timer - that way you won't forget to turn it off. There are even combo timer switches that will turn the fan on when you turn the lights on, then leave the fan on for 20min after you turn the lights off. If noise is a concern, I wouldn't use a mechanical twist timer. Leviton makes a nice electronic push-button timed switch too - push the button for on, and it counts down to off.