A post-occupancy evaluation indicates that occupants are cold during winter months due to the building’s HVAC system not performing according to…

Commissioning is a quality-assurance process that verifies and documents that a building's systems, including HVAC, are planned, installed, tested, and capable of being operated and maintained according to the owner's project requirements and the design intent. A core component of commissioning is functional performance testing, which would have simulated winter conditions to test the HVAC system's heating capacity. This process would have identified that the system was not performing as designed, allowing for corrections to be made before the building was occupied, thereby preventing the issue discovered in the post-occupancy evaluation.

B. additional diffusers: This is a potential design solution, not a quality-assurance process to verify that the existing system performs as specified.

C. a punch (deficiency) list: This is a document that records observed deficiencies near project completion; it is the result of an inspection, not the comprehensive testing process that prevents systemic performance failures.

D. an underfloor distribution system: This is an alternative type of HVAC design, not a process for ensuring that any given system is installed and functioning correctly.

1. ASHRAE Guideline 0-2019

The Commissioning Process. The Foreword and Section 5 describe commissioning as a quality-oriented process to verify and document that building systems (including HVAC) are planned

designed

installed

tested

and operated to meet the Owner’s Project Requirements (OPR). This verification and testing is precisely what would have prevented the issue.

2. Mills

E. (2011). Building Commissioning: A Golden Opportunity for Reducing Energy Costs and Greenhouse-Gas Emissions. Lawrence Berkeley National Laboratory. LBNL-56454 Rev. 2. On page 1

the report states

"Commissioning ensures that the new building operates initially as the owner intended and that building staff are prepared to operate and maintain its systems and equipment." It identifies that HVAC systems are the most common source of problems found during commissioning.

3. University of Washington

College of Built Environments. CM 410: Building Systems. Course materials on Mechanical Systems and Commissioning explain that the commissioning agent's role is to "verify that the systems' performance meets the building's design intent." This directly addresses the failure described in the question ("not performing according to design").