Hamtil Construction LLC
Hamtil Construction LLC
  • Hometalker
  • Saint Louis, MO

Is Your Bathroom Properly Ventilated?


We've seen it probably more than 100 times. In an attic, the bath fan discharges directly into a pile of insulation. You would be surprised that it's more common than many people realize! If you don't know the condition of yours, it's worth a quick investigation. So, what are the indicators of a properly ventilated bathroom? Here are a few tips.

1. Select the correct size bath fan. Many have a square
is your bathroom properly ventilated, home maintenance repairs, how to, hvac, This preset bath fan timer is a great solution for ensuring the bath fan runs for an adequate amount of time The 30 minute preset is typically used for showering
This preset bath fan timer is a great solution for ensuring the bath fan runs for an adequate amount of time. The 30 minute preset is typically used for showering.
is your bathroom properly ventilated, home maintenance repairs, how to, hvac, The duct shown is terminated to the exterior which is required by code in most areas Minimize the twists turns and fittings used in the ductwork for the best airflow
The duct shown is terminated to the exterior, which is required by code in most areas. Minimize the twists, turns, and fittings used in the ductwork for the best airflow.
is your bathroom properly ventilated, home maintenance repairs, how to, hvac, The paper test in action
The "paper test" in action.
is your bathroom properly ventilated, home maintenance repairs, how to, hvac, Ensure proper make up air because that is usually the only spot where it is drawn from during a shower
Ensure proper make up air, because that is usually the only spot where it is drawn from during a shower.

Have a question about this project?

Join the conversation

2 of 26 comments
  • Hi Khol, thanks for the comment. I would suggest an 80cfm fan. Definitely wise to terminate to the exterior. I would try to keep the ducts separate if possible, just so you do not lose airflow, but I understand that it's not always possible. Also, one thing to keep in mind, is that a vertical pipe can sometimes leak condensation back downward (steamy shower, cold air in the walls/ attic). If you must do it this way, be sure to insulate the pipe, at least in the attic space. Definitely need to saw the door bottom too! Best of luck.

  • Hi @Cherie Dunkel-Hoysock - I am just revisiting this thread, saw your comments, and I was curious if you ever resolved your sewer/ vent issue?

Your comment...