Treat ventilation as a system
A fan’s label alone does not guarantee performance. Duct length, elbows, termination, backdraft protection, make-up air and installation quality can affect actual airflow. Use manufacturer instructions and local code requirements when selecting and installing equipment.
Exhaust outdoors
Bathroom exhaust should be routed to an appropriate exterior termination rather than dumping moisture into an attic, wall cavity or other concealed space. The exact routing and termination rules vary by building type and jurisdiction.
Give moisture time to clear
Controls can help the fan continue operating after bathing. The best strategy depends on climate, household habits and the ventilation system. Keep grilles clean and confirm that exterior dampers are not obstructed.
Watch for persistent symptoms
Recurring condensation, peeling finishes, musty odours or staining can indicate that moisture is not being controlled. These signs warrant investigation rather than simply applying another coat of paint.