Buildings don’t always perform as intended once they’re occupied.
Occupants may complain about being too hot or cold, energy use might be higher than expected and systems could operate differently to the originally anticipated usage patterns. Facilities teams then spend time and effort reacting to these issues without clear performance data or direction.
Over time, incremental changes such as setpoint adjustments, seasonal variation and equipment degradation lead to a gradual decline in heating, ventilation and cooling (HVAC) performance. The building drifts away from its original design intent, often referred to as the performance gap.
Ongoing commissioning activity help keeps your building on track with its original design intent so people stay comfortable at the lowest practical energy use.
Why buildings don’t perform as intended
A drift is expected in operational buildings because design assumptions rarely match real occupancy and usage patterns. Once operational, systems and controls can experience issues that ultimately impact real-world performance. Reasons for this include:
- Seasonal conditions reveal issues that weren’t apparent at the time of design and handover, and many buildings aren’t tested at peak load or over different seasons.
- Program pressure to reach practical completion on time can also limit commissioning and testing during construction.
Without a structured process, building adjustments become reactive to the loudest issue rather than being managed against defined performance outcomes.
Ongoing commissioning addresses this by treating building performance as something that requires regular verification and adjustment.
Optimising building performance through ongoing commissioning
We recommend a commissioning team stays involved beyond handover so they can work with owners and facilities teams to maintain performance levels of systems over time.
The independent commissioning team can then:
- review design intent and confirm systems are still performing effectively compared to the original commissioned or measurable outcomes
- agree performance targets for comfort, energy and operation with key stakeholders
- carry out seasonal commissioning and testing under actual occupancy conditions
- use BMS data and metering to identify issues and prioritise actions
- provide practical guidance and training for the facilities teams and building users
- carry out regular performance reviews and close out of identified issues.
By making outcomes measurable, testing systems in different seasons and using actual in-use data to guide decision making, systems can be optimised to reduce, or prevent, the performance gap.
What does ongoing commissioning look like?
Ongoing commissioning is most effective when it forms part of a broader, structured process where:
- commissioning begins in design and continues through construction and handover
- soft landings support the transition to operation, preparing facilities teams
- ongoing commissioning maintains performance during operation
- building tuning is used to adjust setpoints, schedules and control strategies, where necessary
- systems are tested under seasonal and real-world operating conditions
- trend data is used to support decisions.
What this delivers for owners and occupants
We’ve supported clients in maintaining building performance after handover through a structured ongoing commissioning approach. This has led to:
- more consistent comfort conditions and improved indoor air quality
- reduced energy use and lower peak demand
- fewer reactive maintenance issues and complaints
- faster identification and resolution of faults using operational data
- more stable transition to steady state operation
- improved asset performance over time.
Commissioning shouldn’t stop at handover. Treat building performance as something you verify and adjust regularly once in use.
Involving an independent commissioning team beyond handover helps keep systems operating as intended in real conditions, saving time, money and stress for asset owners and facilities teams.
