The majority of new home construction is deadline-driven, which means that, sometimes, minor but essential work may be performed haphazardly or not at all. This is especially true of sealing around exhaust fans and ductwork. If the opening cut for the installation of the fan box or duct leaves large gaps around the unit, air can escape into unconditioned spaces and create airflow and moisture problems that don’t reveal themselves until they become critical. Proper installation at the outset can help prevent such issues. Inspectors can read more about them in Inspecting for Air Sealing at Kitchen and Bathroom Exhaust Fans.