Designing Kitchens and Bathrooms - Bathroom needs exhaust fan

I have a question regarding installing an exhaust fan in a very old bathroom. The house has an attic, but the attic doesn't run the full length of the house. The bathroom shares a wall with an after-thought laundry room. I am not sure where to install the exhaust fan due to the fact that the we live in SE WA state and it is cooooold most of the year. Does anyone have any suggestions? Thank you.

Hi, Most definitely vent the fan to the outside...not just into the attic or the laundry room! (mositure problems. code too probably) The fans I have experienced have a backdraft (if you will) flap. You could also install an end fitting or cap that has a flap also so that it would keep cold air out until the blower's pressure opens it. We installed one in a house that had moisture problems. So far so good. The quiet ones are great! We vented it out under the eaves so as not to have to cut a hole in the roof. We vented it between the joist runs by cutting the drywall out (careful not to cut the joists of course) big enough for the fan and the ducting...installed the housing, then the ducting and then the fan, replaced the drywall...and done! In other words we did not need to get into the attic space...just needed enough clearance for the fan, (stats were listed on the info that came with the fan. Hope that was of some help.
I think if the area hadn't lended itself to our plan so conveinently, we would have gone for the hole in the roof route. (Not in too cold an area but we are energy conservative...we keep the bath door closed when not in it so as to keep the preferred temp air in the core of the house.)
Good luck!

Thank you j&n!!