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Ongoing Commissioning

Category: Behavior Changes, Energy Efficiency

Ongoing commissioning is the process of optimizing and sustaining building performance through repeated cycles of investigation, analysis, and monitoring of building systems. It can be defined as the frequent repetition of the retro-commissioning process. Mechanical, HVAC, lighting, and domestic hot water systems can all benefit from ongoing commissioning. 

When done correctly, ongoing commissioning optimizes building performance, reduces energy consumption and operating costs, and prevents problems throughout the building’s lifetime. It can also proactively address occupant discomfort or dissatisfaction by discovering and resolving problems early on. Finally, like retro-commissioning, ongoing commissioning can improve the energy or sustainability ratings of existing buildings without requiring new construction. These aforementioned reasons make ongoing commissioning a cost- and resource-efficient way to achieve campus sustainability goals. 

Ongoing Commissioning happens through continuous repetition of the following steps:

  • Planning and investigation. Create a plan that sets measurable goals and outcomes for the building’s performance. The plan should provide clear direction for the kind of functional tests that you intend to perform routinely. Conduct an ongoing site assessment to inform recommendations for further testing and corrective actions. 
  • Data Monitoring. Conduct continuous data collection and analysis in order to monitor and assess performance of commissioned systems. This step requires a definition of the data points that will be continuously monitored, the frequency of data collection, and analytics to be used.
  • Functional testing and performance verification. Functional testing sets a framework for identifying and categorizing problems by priority in order to determine when action should be taken. Establish categories of problem severity and predetermine what level of severity will trigger a corrective action response.
  • Corrective Action Response. Repair problems of sufficient severity. Ensure that operations staff are trained in using and preserving the life of any new equipment.


  • Quickly realize energy and resource savings
  • Buildings operate to meet current demands and requirements based on actual conditions
  • Improve the comfort, health and safety of building occupants
  • Detect and resolve problems early
  • Reduced maintenance costs


  • Data collection and ongoing monitoring may be technically difficult to implement
  • Requires training and additional tasks for operational staff
  • Overcoming the “way we always did it” mentality




  • GHG Impact


    In 2011, Harvard saw a reduction of 800 MTCDE for a 135k sf building.


  • Economic Impact

    Net Savings

    The payback period is typically one to two years. 

  • Feasibility

    Some Challenges

    Continuous commissioning’s biggest costs are often time and labor with very little capital costs.

  • Timeline

    < 1 year

    Minimum monitoring time should be 1 year to verify annual  performance improvements.

  • Maintenance


    Overall maintenance costs will be reduced by active monitoring of building systems over time.

  • Publicity

    Under the radar

    Operational improvements greatly benefit occupants and bottom line, but they may have limited PR value.