Making Commissioning clear


What is it?


The application of the commissioning process to an existing building that has not previously undergone the commissioning process.



Retro-Commissioning typically focuses on energy-using equipment such as mechanical equipment, lighting and related controls and usually optimizes existing system performance, rather than relying on major equipment replacement, typically resulting in improved indoor air quality, comfort, controls, energy and resource efficiency.


Retro-Commissioning typically includes an audit of the entire building including a study of past utility bills, interviews with facility personnel. Then diagnostic monitoring and functional tests of building systems are executed and analyzed. Building systems are retested and remonitored to fine-tune improvements. This process helps find and repair operational problems. The identification of more complex problems are presented to the owner as well. A final report, recommissioning plan and schedule are then given to the owner.




The basic phases and the goals of each phase of the Retro-Commissioning process are as follows:


Planning Phase: Development of the Commissioning goals, facility requirements, and a commissioning plan.

Select the project
• Set project objectives and obtain support
• Select a commissioning lead
• Document the current operating requirements
• Perform an initial site walk-through
• Develop the Retrocommissioning Plan
• Assemble the retrocommissioning team
• Hold a project kick-off meeting

Investigation Phase: Field inspections, data gathering, testing and analysis to accurately assess system performance and identify improvement opportunities.

• Review facility documentation
• Perform diagnostic monitoring
• Perform functional tests
• Perform simple repairs
• Develop Master List of Findings
• Prioritize and select operational improvements

Implementation Phase: The desired facility improvements are completed and the results and performance are verified.

• Develop Implementation Plan
• Implement selected operational improvements
• Verify results

Turnover Phase: The systematic transition from a commissioning activity and the commissioning team to standard operating practice and the operations and maintenance team.

• Develop Final Report
• Compile a Systems Manual
• Develop Recommissioning Plan
• Provide training
• Hold close-out meeting
• Implement persistence strategies

Persistence Phase: Implementation of systems and tools to support both the persistence of benefits and continuous performance improvement over time.

The owner should consider implementing one or more strategies that help to ensure that the energy savings – and other benefits – from the retrocommissioning
project are long-lasting. Common strategies for ensuring persistence include:

• Developing policies and procedures for updating building documentation. For example, correcting the building's drawings to reflect any changes as they occur. Most importantly, immediately documenting any changes to sequences of operation or control strategies that affect the retrocommissioning improvements

• Providing ongoing training for building staff

• Enhancing the current preventive maintenance program to include upkeep of sound operating practices and strategies

• Tracking whole-building energy performance

• Periodically recommissioning the building, paying close attention that the original retrocommissioning improvements are still producing benefits Instituting a plan of "ongoing" or "monitoring-based commissioning"


Getting Started


• Please see "Getting Started" within Existing Building Commissioning for details.