My old bathroom vent was just vented into the attic and I would like to run it to the side of my house and that is about 22-25 feet. My bathroom is 11'x6' with a 110 cfm fan. I live in Southeast PA.

Would that be ok?

Also I would like to use 4" insulated rigid pipe but I can't seem to find any? Home depot carries insulation sleeves for 6" but not 4".

  • Wow that is a long run don’t use flex use straight pipe sections and try to limit bends but this will be 1000x better than dumping into the attic. – Ed Beal Aug 21 '19 at 15:33
  • If you ever replace your bathroom vent you might want to beef up the cfm. – JACK Aug 21 '19 at 15:38
  • you might consider a wider duct than normal or a stronger fan. see how it works, adjust as needed. – dandavis Aug 21 '19 at 16:44
  • @dandavis OP needs to take little bit of caution if increasing duct size. If you go too large over a certain distance, the lesser differential pressure may not be enough to overcome the back draft damper on the exhaust louver on the exterior of the house. Just make sure the exhaust louver opens when activating the fan after installing it. Also, the lower exhaust velocity may collect more condensation on the inside of the duct because of the increased duct surface area and relative less airflow. Not a huge deal, but I figured I'd mention it – Dotes Aug 21 '19 at 17:09
  • 1
    @Dotes: good call. i should have said and/or (maybe just and)... the 6" insulation mentioned led me to believe that would be applied, which would help with the inner condensation. – dandavis Aug 21 '19 at 17:12

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