Some projects have a commissioning component, which essentially confirms for the owner that the design produced by the design team (architects/engineers) is installed and operating per the design intent. The commissioning agent performs functional tests to ensure that the design (namely HVAC) and install are the same. If the system is not performing as designed, tests are performed to discover why and what needs to be fixed and/or changed. Enhanced commissioning takes this a step further and reviews the plans during design to make sure that there is proper access to vital pieces of equipment (motors, valves, etc.).
While we feel that commissioning is generally a good idea, it is also not always required unless it is a LEED certified project – provided that the design is thorough and complete, the mechanical contractors produce high-quality work, and the test and balance (TAB) contractor is methodical and comprehensive. Commissioning can also be expensive, and again, if all of the above is true, it can be expensive.