Commercial Financing, Units, Doors, and Keys

A commercial property developer may sometimes refer to a 200-unit apartment building as a multi-family project with 200 doors.  It means the same thing.  The slang term, "doors", is used in connection with apartment buildings.

A hotel developer may describe a 200-room hotel as a hotel with 200 keys.  The need for the term keys arose when hotels started to contain more suites.  A suite has two or more rooms, so use of the term rooms in connection with a hotel became confusing.  A hotel with 160 regular rooms and 40 suites would be described as having 200 keys.