Commissioning is a quality-assurance process used to verify that a building performs according to the original design and intent and meets the needs of the owners and occupants. Federal agencies are required to make sure building systems and equipment are commissioned in new construction and existing buildings. 

Commissioning Types

Commissioning in New Construction and Major Renovations

This is done to ensure that systems, subsystems, and equipment in new buildings operate properly. It includes performing design reviews, functional testing, system documentation, and operator training throughout the project to make sure the building meets the requirements as intended by each building owner and as designed by the building architects and engineers.

Ongoing Commissioning in Existing Buildings

Ongoing commissioning (OCx) is a term that appears in the U.S. Green Building Council’s (USGBC) Leadership in Energy and Environmental Design O+M: Existing Buildings. According to USGBC, it is described as a "process that includes planning, point monitoring, system testing, performance verification, corrective action response, ongoing measurement, and documentation to proactively address operating problems in the systems being commissioned." Several currently practiced OCx approaches are available, including continuous commissioning and monitoring-based commissioning/real-time commissioning. Each has its own approach and methodology.

This ongoing process is designed to resolve operating problems, improve comfort, optimize energy use, and identify retrofits for existing buildings. Although it is ideal for large complex buildings with automation and advanced metering systems, ongoing commissioning is the most costly approach for existing buildings because of staff and equipment allocations. However, the process can identify equipment inefficiencies as they occur and allow for quick remediation and greater energy and cost savings.

Recommissioning in Existing Buildings

As defined in 42 U.S.C. 8253(f)(1)(F), “recommissioning means a process – (i) of commissioning a facility or system beyond the project development and warranty phases of the facility or system; and (ii) the primary goal of which is to ensure optimum performance of a facility, in accordance with design or current operating needs, over the useful life of the facility, while meeting building occupancy requirements.”

In practice, recommissioning (ReCx) is accomplished through testing and adjusting the building systems to meet the original design intent or optimize systems to satisfy current operational needs. ReCx relies on building and equipment documentation, along with functional testing to optimize performance. ReCx is applied to buildings that have been previously commissioned—either as new or existing buildings.

This is done to ensure that systems and equipment in existing buildings meet the original design intent. ReCx is used in buildings that were previously commissioned to fine-tune them to meet their original design intents and operational efficiencies. ReCx should be considered for new buildings that were commissioned during construction and in which energy needs have increased.

Retro-Commissioning in Existing Buildings

42 U.S.C. 8253(f)(1)(G) defines retro-commissioning (RCx) as “a process of commissioning a facility or system that was not commissioned at the time of construction of the facility or system.” Like new building commissioning, RCx is concerned with how equipment, systems, and subsystems function together, but it does not generally take a whole-building approach to efficiency.

The process can identify and solve problems that occurred at construction but also addresses problems that have developed to this stage in the building’s life. While the goal of RCx may be to bring the building, its systems, and equipment back to its original design intent, that is not a requirement. Depending on the building's age, RCx can often resolve problems that occurred during design or construction (for buildings that did not undergo the commissioning process during the design and construction process), or address problems that have developed throughout the building's life. In all, RCx improves a building's operations and maintenance procedures to enhance overall building performance.

This is done to optimize systems to meet new operational needs through testing and adjusting. RCx is used in older buildings that have never been through the commissioning process. RCx should be considered if building systems are old, expensive to operate, and have frequent equipment failures.

What type of commissioning should I use?

Consider:If Your Building Is:This Type of Commissioning Is Ideal For:
CommissioningNew construction or undergoing major renovationMaking sure new buildings meet all their intended design and operational intents
Ongoing CommissioningLarge and complex and has high energy use and frequent tenant complaintsBuildings with metering systems and preventive maintenance programs
RecommissioningRelatively new and was commissioned during constructionBuildings that need to be fine-tuned to meet increasing energy needs or return to their original design operational intents
Retro-CommissioningOld and expensive to operate and experiencing frequent equipment failuresOlder buildings that were never commissioned

Key Resources

Recommended FEMP Courses

Need Assistance?

Need energy management guidance? Can't find a document or tool? FEMP can help. Ask FEMP a question.