Energy auditors write them up. Should home inspectors, too?
Consider the following:
Creating a negative pressure inside the house draws in outside moisture and pollutants. (Crawlspace environments are actually sucked into the living space).
Imagine a small fire starting in the home while the fan is on and the family is sleeping. Will the fan draw smoke past the smoke detection system too quickly to be detected while drawing more air for the flames?
Is the attic adequately vented … not just for the excess moisture, but to expel 1200 to 2000 CFM?
When they are off, they represent a penetration in the thermal boundary of the home and contribute to air leakage.