I am a highly skilled home service professional. I recently completed a job where I replaced a bath fan that was backdrafting into a bathroom. The customer had noticed a conversation around the vent next to the bath fan, which was causing concern. I inspected the fan and found that it did not have a damper installed, which was the cause of the backdrafting. I provided the customer with an estimate for the replacement of the bath fan, and they agreed to move forward with the project.