One reason is that the duct connecting to the fan does not actually reach to the outside of the house, instead it might only be ventilated into the attic space. While you may feel that this doesn’t affect the bathroom it can cause problems in the attic, creating an environment which will cause decaying of materials and mold.
Another reason a bathroom exhaust fan will stop working properly is if it becomes clogged with dirt and dust. This is a problem easily fixed with cleaning.
As home inspectors, we know what to check for to make sure the ventilation system is working properly. If you notice things like excessive moisture on the walls of your bathroom, metal fixtures starting to corrode, peeling or bubbling paint on the walls or high levels of humidity, these might be a sign that the ventilation system is not working. Please feel free to contact us if you would like an inspection of your bathroom ventilation system.