Ask a Connecticut restaurant owner what "ventilation cleaning" includes and you will often get three different answers, and the quote in your inbox may cover only part of the system. The hood over your line is the visible piece. Behind it sit grease filters, a duct run that can climb through several floors, an exhaust fan on the roof, and in many buildings a makeup air unit that replaces the air you pull out. Treating these as one job is how a kitchen ends up with a clean hoo