Glossary
Commissioning (Cx)
Plain-Language Definition
A quality assurance process that verifies building systems are designed, installed, tested, and capable of being operated and maintained according to the owner's requirements.
Technical Context
ASHRAE Guideline 0 defines the commissioning process. It spans four phases: pre-design (OPR development), design (basis of design review), construction (functional performance testing), and occupancy (seasonal testing, training). Retro-commissioning (RCx) applies the process to existing buildings. Enhanced commissioning extends the process with independent review. LEED requires fundamental commissioning and awards additional points for enhanced commissioning.
Why It Matters
Studies show that 50-70% of buildings do not perform as designed. Commissioning closes this gap by systematically verifying performance. The median cost of commissioning is 0.4% of construction cost, with energy savings of 13-20% and non-energy benefits including fewer change orders, reduced warranty callbacks, and faster occupancy.
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