Bath exhaust fan with in/outside diverter
 

We are in the initial stages of planning for redoing our bathroom. Our house is fairly leaky, so in winter, we tend to put a pedestal fan blowing air into the bathroom to get some moisture in the house as well as retain some of the heat from the shower. So, I thought why not do a bathroom fan that vents to another part of the house as well as outside? It could vent to the hallway pretty easily with a little ducting in the attic. A diverter can be used to vent air outside in the summer.

What do you guys think? Do you see any issues with this? My only concern would be moisture build up in the ducting in the attic.

Here is an image to show the idea a bit better.

https://ecorenovator.org/forum/attac...1&d=1559411531

You might as well just leave the fan off when you take a shower and open the door immediately(leave it open) when you get out of the shower to bring the moisture down in the bathroom to disperse the moisture to the rest of the house if you are trying to raise the humidity to the rest of the house. If that's too much moisture, have the fan running during the shower, shut it off right when you get out and then open the door.

If you really want the moisture and nobody else cares in the house, leave the door open for the whole shower and you'll raise that humidity like crazy.

...I have the opposite problem, I run the fan for the full duration of the shower plus another 10 minutes while the door is still closed and I barely to keep the moisture in the house as low as I'd like throughout the winter apart from January and February when the outdoor dew point is super low and there is more induced air leakage because of the temperature difference. Air sealing will get you to that point, if you are in need of adding bulk moisture, you are venting a significant amount of the moisture you already have when it gets replaced with the outdoor air.

Right now we already do leave the door open. We also run a pedestal fan blowing into the bathroom during or shortly after the shower to vent the moisture and heat out. We have had mold issues in the room, but are being more careful now. I was thinking the new fan could eliminate the pedestal fan as its annoying and gets in the way.