Commissioning (Cx) is a quality process that verifies, documents and ensures that a building's technical systems operate in line with the design intent (Owner's Project Requirements) and contractual performance. In HVAC, it covers all heating, ventilation and air conditioning systems.
The phases of commissioning according to ASHRAE
ASHRAE Guideline 0 defines a four-phase process that structures commissioning from design through to operation:
- • Phase 1 — Pre-design: definition of the Owner's Project Requirements (OPR) and identification of critical systems.
- • Phase 2 — Design: review of drawings and specifications, drafting of the commissioning plan, identification of checkpoints.
- • Phase 3 — Construction: site inspections, verification of installation compliance, pre-functional checks.
- • Phase 4 — Handover/Operation: functional tests, performance tests, training of operations staff, post-handover follow-up.
Why commissioning has become essential in 2026
- • RE2020 (French building regulations): the energy performance requirements (Cep, Bbio) cannot be met without rigorous commissioning.
- • Tertiary Decree (French energy-reduction regulation for commercial buildings): the reduction targets (-40% by 2030) require accurate consumption monitoring from handover.
- • Environmental certifications: HQE, BREEAM and LEED require documented commissioning to earn credits.
- • Claims: according to AQC (the French construction quality agency), 30% of building defects relate to HVAC packages — commissioning reduces this risk.
- • Energy performance guarantees (GPE): more and more contracts include quantified commitments.
Essential functional tests
- • Verification of air and water flow rates on every piece of equipment (AHUs, terminal units, pumps).
- • Testing of control sequences: start-up, shutdown, heating/cooling changeover, fallback modes.
- • Ductwork air-tightness tests (class A, B or C according to NF EN 16798).
- • Measurement of noise levels in sensitive rooms.
- • Verification of the BMS: alarm reporting and data logging.
- • Testing of the boiler or heat pump cascade at full and part load.
Commissioning is not a one-off check — it is a continuous process. Schedule follow-up visits 6 and 12 months after handover to identify seasonal drift.
The role of the commissioning agent
The commissioning agent (CxA) is an independent third party, separate from the design engineers and the commissioning contractor. This independence guarantees objective verification. The CxA coordinates the tests, writes the test procedures, records the results and raises snagging items. In France, this role is often filled by the commissioning engineer or a specialist technical client's advisor.
In 2026, commissioning is no longer a luxury reserved for large projects: it is quality assurance that protects the building owner, showcases the work of the commissioning engineer and secures the real-world performance of the building.