Commissioning Verifies That Building Systems Actually Perform the Way They Were Designed to Perform
A building can be constructed exactly as designed and still not perform as intended. Mechanical systems that are correctly installed but incorrectly balanced, building automation controls that are wired but not programmed, ventilation systems that meet code requirements at design conditions but fail under actual occupancy loads - these are the failures that commissioning is designed to prevent. Building commissioning (Cx) is the systematic process of verifying and documenting that all building systems (HVAC, electrical, plumbing, lighting controls, building envelope, and others) are installed, tested, and calibrated to operate as specified. Understanding what commissioning is, who does it, what it covers, and when it occurs in the project timeline is tested on both the ARE PDD (project delivery and documentation) and CE (construction and evaluation) exams.
The Commissioning Authority
The commissioning process is led by a Commissioning Authority (CxA) - an independent third party (typically a specialized commissioning consultant) who is not directly involved in the design or construction of the building systems being commissioned. The independence of the CxA is critical to the credibility of the commissioning process: an HVAC contractor commissioning their own work is not the same as an independent expert verifying that the HVAC contractor's work performs correctly. The CxA is typically hired by the owner directly, with coordination through the architect, and begins their work during the design phase (developing the commissioning plan) and continues through construction and into occupancy.
Fundamental vs. Enhanced Commissioning
Fundamental commissioning (required as a prerequisite for LEED certification) covers the basic HVAC and mechanical systems: air handling units, terminal units (VAV boxes, fan coils), boilers, chillers, cooling towers, pumps, controls, and building automation systems. Testing and verification confirms that each piece of equipment starts, operates, and shuts down correctly; that control sequences function as specified; and that the overall system achieves the required heating, cooling, and ventilation capacity under occupied conditions.
Enhanced commissioning (an additional LEED credit, EA Credit: Enhanced Commissioning) extends the process: the CxA reviews design documents and specifications during design, verifies commissioning-friendly features are incorporated into the design before construction, and performs post-occupancy monitoring (typically 10 months after occupancy, before the first-year warranty expires) to identify any system performance issues that only emerge under actual operating conditions.
Commissioning During Construction
During construction, the CxA: reviews shop drawings and submittals for mechanical systems; observes factory testing of major equipment; witnesses installation and start-up of equipment; develops testing and balancing protocols; witnesses or performs testing (verifying that the HVAC system can achieve design conditions, that air flow rates are within specified ranges, that controls function correctly); and documents all findings in a commissioning report. Any deficiencies discovered during commissioning testing are reported to the owner and contractor for correction.
Key Exam Points
- Commissioning: verifies building systems are installed and operate as specified.
- Commissioning Authority (CxA): independent third party; hired by owner; independent of design/construction team.
- Fundamental commissioning: required LEED prerequisite; covers HVAC and mechanical systems.
- Enhanced commissioning: LEED credit; adds design review, more systems, post-occupancy monitoring.
- CxA starts in design phase; continues through construction and into first year of occupancy.
Study PDD on AREprep
AREprep’s PDD flashcards cover every concept on this exam with spaced repetition, and the practice exams mirror the real question formats so the actual test feels familiar.