Originally Posted by david szela
the problem with going thru the roof that i read was that the condensation will go back down into the bathroom / fan because the vent is directly above it and that is true because it happened to a friend of mine .maybe if there is a bend or not just straight above it. it wouldnt be a problem. he does have an older fan
The LAST thing you want to do is put warm moist air in your attic.
If the fan does not have enough velocity, I could see how maybe that might happen.
Insulating the pipe in the attic would help cut down any condensation in the pipe. Of course, a side exit would be your best option to eliminate condensation coming back.
If your looking for a fan now, pay attention to the CFM and Sones (noise). There are charts out there that suggest what CFM you need for a given size bathroom. And getting a quiet fan reduces the irratation factor. I personally hate loud bathroom fans.