Retro-Commissioning (RCx) and LEED Existing Buildings: Operations and Maintenance

Healthy Buildings’ Retro-Commissioning (RCx) Approach

Retro-commissioning (RCx) is a systematic process developed to evaluate, document, and improve the operation of building energy using systems. Applying a comprehensive RCx process can be a very cost effective way to identify and implement measures to reduce energy use and cost while improving system operation and occupant comfort in existing buildings. However, an extensive process may not be appropriate for every facility. Feasibility studies can be a useful tool to determine which facilities are best suited to undergo an RCx effort, and to what level. Identifying those buildings with greater opportunities allows property owners / portfolio managers to make educated business decisions on how best to allocate financial resources.

While documenting the program is an absolutely critical step in any RCx effort, Healthy Buildings believes maximum benefit is achieved through a rigorous “rubber-meets-the-road” approach rather than “executive” level paperwork process. Detailed functional performance test procedures methodically put building equipment / systems through their operational ranges. RCx value is maximized when the commissioning agent (CA) directly applies years of hands-on knowledge and experience to those systems as the test procedures are executed. However, test procedures in which systems are manipulated do not always tell the whole story. In conjunction with manual testing, building automation system (BAS) trend analysis and stand-alone data logging provide the CA with valuable information for a complete picture of system operation.

The process will undoubtedly discover system issues and identify areas for improvement. As a result, RCx can become adversarial or fail to realize full potential if operators are made to feel defensive. Therefore a key component to any successful RCx program is collaboration, and HBS works very deliberately to build a team approach. In addition to facilitating the process, including staff provides other tangible benefits. Living with the building every day, operators are a great source of information. A deeper understanding about “why and how” system modifications are implemented alleviates “well, that’s not how we’ve always done it”, and there is a much greater chance the improvements will be maintained, or improved, over time.