Decoding Existing Building Commissioning

Existing Building Commissioning

What’s the difference between Re-Commissioning and Retro or Existing Building Commissioning? How can data support buildings that have been heavily renovated? And how does building data support Energy Conservation Measures (ECM) changes? Discover the answers to these questions and how building commissioning with data analytics can validate your building performance.


Re-Commissioning (RCx) involves the assessment and optimization of existing building systems to ensure they are operating at their peak performance. It aims to identify and resolve operational inefficiencies, equipment malfunctions, and other issues that may have arisen since the initial commissioning or due to changes in building usage. It is typically performed on previously commissioned buildings, but may have experienced changes in occupancy, equipment upgrades, or other modifications over time. The goal of re-commissioning is to identify any operational inefficiencies, malfunctions, or deviations from the original design intent and to implement corrective measures to restore optimal performance. This process may include functional testing, data analysis, equipment calibration, control system optimization, and the documentation of updated operating procedures. Re-commissioning helps improve energy efficiency, occupant comfort, and overall system reliability, while also ensuring that the building continues to meet the evolving needs of its occupants and stakeholders. It is a valuable tool for optimizing the performance and extending the lifespan of existing buildings.

Existing Building Commissioning (Retro Commissioning)

Existing Building Commissioning (EBCx), also known as Retro Commissioning (RCx), is a systematic process that focuses specifically on buildings that have never undergone commissioning and involves a thorough examination of systems, identification of deficiencies, and implementation of improvements to enhance energy efficiency, occupant comfort, and overall performance.  It involves a thorough assessment and evaluation of building systems, including mechanical, electrical, and control systems, to identify and address inefficiencies, malfunctions, and performance gaps. This process typically includes data analysis, functional testing, system adjustments, and ongoing monitoring to ensure sustained improvements. EBC/RCx offers an opportunity for building owners to maximize the value of their existing assets, reduce operating costs, and extend the lifespan of building systems while creating a more comfortable and sustainable environment for occupants.

Energy Conservation Measures (ECM)

Building data plays a crucial role in supporting Energy Conservation Measures (ECM) changes discovered during Existing Building Commissioning. By collecting energy consumption data, occupancy patterns, and other relevant metrics, building owners can assess the impact of ECM implementations and track their effectiveness in reducing energy usage. Data analytics allows for the identification of energy-saving opportunities, measurement of energy savings, and adjustment of strategies as needed. It enables continuous improvement and validation of the ECM measures, ensuring that the building operates efficiently while minimizing energy costs and environmental impact. This data-supported approach is especially valuable in heavily renovated buildings where new systems and components are integrated, ensuring that they function as intended and achieve desired performance levels.

Click to watch this brief video Decoding Building Commissioning.