I am replacing my 25 year old bathroom fan.
Should I keep the existing vent pipe setup or should replace it by a separate roof jack?
Your photo shows the stack going up "somewhere". It should be vented to the outside. (OBTW, size and length DO matter here). ;-)
Check out the Panasonic Whisper fans site for proper installation of fans whatever brand you select.
I am not a rep for Panasonic, but I have two of their fans, can barely hear them when they are on, they are on timers, and am very, very, VERY pleased with them.
Here is a link that might be useful: Panasonic Installation guide
Yeah, the vent goes to the opening in roof that is used for attic venting. I just wonder if it could be a problem.
Yes, I have already got Panasonic fan as a replacement.