By Nicole Imeson, P.L.(Eng.)

Since the inception of the Building Commissioning Association (BCxA) in 1998, members and volunteers spend hundreds of hours each year developing best practices, educating Commissioning Providers (CxPs), and striving to make commissioning' business as usual.' Over time, commissioning scopes have expanded to more than just HVAC systems, and today they often include lighting systems and controls, building enclosure assemblies, integration testing, security systems, energy management information systems, and numerous others. The BCxA has participated in numerous research projects which demonstrate how various commissioning processes result in direct economic benefits to building owners.

New Construction Commissioning (NCCx) 

There are many benefits to commissioning a new building, although some are harder to quantify than others. When the CxP is engaged at the beginning of a project — as the BCxA Best Practices recommend — they define the owner's project requirements (OPR) and set clear guidelines and performance metrics. Having these documented before anyone else is engaged in the project sets clear expectations and mitigates rework that would occur if those objectives were defined at later stages. An earlier checklist article discussed how the OPR is a living document used throughout a project to ensure the design and construction stay on track, and the end result meets the owner's goals and objectives.   

As part of the design phase, the CxP completes a technical design review to confirm the general quality and completeness of the documents, review system operation and performance for compliance with the OPR, confirm the basis of design (BOD) is accurate, and confirm the design is feasible to commission, install, and maintain.

In 2018, the BCxA completed a Market Survey exploring the Value of Commissioning, in which CxPs reported 25% of total construction issues were discovered during the design phase. Modifications to the contract documents during design can be implemented with minimal impact on resources and schedules. However, once construction has started, altering designs often requires reworking drawings or installation on site, issuing change orders, reviewing pricing, re-reviewing submittals, adding field time for coordination, and impacting the project schedule and budget. Addressing construction issues early during design represents high value, low cost, and good return on investment for owners.  

While there is inter-discipline coordination amongst the design team, the CxP is often the only party reviewing the entire package with a technical eye on behalf of the owner. The Cx design phase review translates to better-coordinated drawing packages, where avoiding something as small as mismatched voltages between the mechanical and electrical drawings can lead to extras once the project enters the construction stage. 
Having completed a detailed design review and with intimate knowledge of the contract documents, the CxP works with the construction team to ensure the installation maintains the same level of operation and performance. The CxP facilitates a smooth turnover between occupancy and operations, a stronger operations team who have completed training of the system, and fewer warranty callbacks since the CxP has completed functional checks of the equipment installation and operation.  

A 2020 report by the Lawrence Berkeley National Laboratory (LBNL) looked at Building Commissioning Costs and Savings Across Three Decades. The report, which evaluated 140 NCCx projects, is the largest known study on commissioning results with respect to savings potential, cost-effectiveness, and commissioning delivery models. The findings reported for NCCx note the median energy savings was 13%, the cost of commissioning per square foot was $1.03 USD, and the simple payback was 4.2 years. These savings only look at tangible costs and don't include time saved for the operations, construction, and design teams to troubleshoot system issues. 

  LBNL Report — Table 8 Key Cost/Benefit Metrics 

Existing Building Commissioning (EBCx) 

The benefits of EBCx are much more tangible and easier to quantify than NCCx since the building has been operating for several years. In an existing building, there is an established benchmark of energy usage, system performance, and occupant comfort, making it easier to calculate savings and paybacks for these projects. The LBNL report reviewed over 650 EBCx projects and found the average payback to be 1.7 years, the median energy savings to be 6.4%, and the cost of the project per square foot to be $0.26 USD. Like new construction, these savings are a comparison of the cost of the commissioning vs. the cost of the repair and do not consider the time saved by operations and contractors to troubleshoot system issues.  

The LBNL report identified several key items EBCx projects aim to resolve, including improved system performance, thermal comfort, and indoor air quality, assisting the owner in qualifying for rebates, financing, or other financial programs, increasing the awareness of operators, and extending equipment life by mitigating short cycling and identifying preventative maintenance. Specific modifications EBCx projects often include are verifying damper and valve operation, adjustments to the operating schedule — ensuring lights turn off and HVAC systems setback temperatures when spaces are unoccupied — balancing airflows throughout the building, minimizing duct leakage, confirming controls components are operational, and checking the sequence of operations of the building automation system. EBCx may also drive large-scale maintenance or operational repairs, such as equipment replacement as those items need to be addressed before functional testing can start. 

BCxA Market Research Report — Figure 18 Reasons for Implementing EBCx 

Ongoing Commissioning (OCx) 

OCx is the means and process to optimize and sustain building performance on an ongoing basis through investigating, analyzing, and monitoring the performance of building systems. As a continuation of the Cx Process typically implemented following NCCx or EBCx, OCx verifies a facility continues to meet current and evolving owner's requirements. OCx process activities occur throughout the life of the facility — some will be close to continuous implementation, and others will be completed as needed. 

The BCxA market research report found an average simple payback of 1.5 years for ongoing commissioning, with most projects seeing full payback between 1-5 years. The results for OCx projects are comparable to EBCx projects since the benchmarks for savings can be easily defined in an existing facility. By continuously tuning the system and collecting data, operators can discover deficiencies and equipment failures quickly, which generates continuous operational savings throughout the life of the building.  

  BCxA Market Research Report — Figure 42 Simple Payback Comparison Between OCx and EBCx 
The LBNL and the BCxA market research reports confirm there is value in commissioning. Not just in project delivery and occupant comfort, but there are quantifiable results in energy savings and operating costs when commissioning projects are implemented on any building. With energy rates continuing to rise, Environmental, Social, and Corporate Governance (ESG) being at the forefront of occupant concerns, and new tools and software development ever-evolving, there is no reason not to explore commissioning on every project.