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What is Existing Building Commissioning (EBCx)?

Like commissioning a ship, commissioning a building ensures a facility’s systems operate as they should, and the building is set to perform at peak efficiency. A building can be commissioned as part of the construction process (new building commissioning) or after the facility is occupied, which is known as existing building commissioning (EBCx). A common benefit of existing building commissioning is that regardless of the process used, most identified energy and cost savings can be obtained with little or no capital improvements. There are a few different types of existing building commissioning, and it is important to understand how they differ in methodology and application. 

What are the different types of EBCx? 

SSR offers several existing building commissioning services: Continuous Commissioning®, retro-commissioning, re-commissioning, and monitoring based commissioning. These each bring value in different situations and can be applied independently or in conjunction with one another.  

Continuous Commissioning®  

Continuous Commissioning® (CCx) is an ongoing process designed to resolve operational issues, improve comfort, and optimize energy use for existing facilities. This is often accomplished through a combination of site surveys, utility analysis, and data analytics in conjunction with the facilities maintenance team and the building automation system. CCx incorporates several sustainability strategies that are used in series to examine and perpetually address elements of existing buildings that can be optimized without the need for heavy capital investment. 

As a licensed process by Texas A&M University Energy Systems Laboratory, SSR’s Continuous Commissioning practitioners have access to the tools, research, and expertise that make the CC process effective. Our select group of engineers and building professionals have the necessary skills and training to quickly identify the best improvement opportunities — those that can be implemented with the least cost while producing the greatest impact. 


Most facilities are designed to operate at a certain level of performance. Over time, a facility’s performance may diminish due to age, inadequate/deferred maintenance, or worn-out equipment. Retro-commissioning (RCx) applies the commissioning process to an existing facility that has not been previously commissioned. It provides an owner with a means to improve the performance of existing buildings by finding ways to optimize systems and upgrade existing equipment with newer and more energy efficient models. 

RCx projects are generally performed in the following order: planning, investigation, implementation, and certification. It is a combination of efforts for analyzing buildings current energy usage, performance issues, and implementing energy conservation measures to reduce operation and maintenance (O&M) costs while improving the functionality of the building’s systems. 

Equipment’s ideal performance and control sequences of operation degrade over time, resulting in system inefficiency, higher O&M costs, and occupancy discomfort. Depending on the age of the building, RCx can often fix these issues created during design or construction and address problems that have developed throughout a building’s life.  


Recommissioning is a process that is applied when a building was previously commissioned. This may be a scheduled part of an ongoing commissioning process or triggered by facility’s change in use, operational problems, or an addition or renovation that impacts major systems. As soon as a building is turned over from construction to operation, systems begin to wear. Even the most energy efficient building systems will begin to deteriorate over time, making the recommissioing process ideal for any facility.  

Monitoring-Based Commissioning  

To help ensure that implemented energy savings strategies continue to be effective and keep the benefits of the commissioning process ongoing, monitoring-based commissioning (MBCx) is a cost effective and valuable service that is easy to deploy. MBCx uses analytical software to continuously monitor critical components of equipment at each facility. This analytical software allows us to run different diagnostic tests to detect and report malfunctioning equipment or systems and observe the overall energy consumption and performance in the building.

To put it concisely, MBCx is a clear, comprehensive, data-based approach to verify that building systems operate according to the design documentation. It consists of building management systems (BMS) analysis, energy meter data analysis, and ongoing commissioning support. As this is an ongoing service, MBCx contracts are typically renewed annually and help maintain optimal operations and efficiency. It is important to note that MBCx brings value to both existing building and new construction projects to help ensure that operational and energy efficiency are maintained on a continuous basis.