For existing building operators and property managers, you have a lot of commissioning options out there – choosing the right one depends on your building optimization goals.
There are a lot of different types of commissioning, each with their own acronym and use case. While the nuances can be subtle, the distinctions make a meaningful difference in scope and expected outcomes.
Here’s the typical menu of options:
- New Construction Commissioning (NCCx)
- Existing Building Commissioning (EBCx)
- Also referred to as Retro-Commissioning (RCx)
- Ongoing Commissioning (OCx)
- Also referred to as Monitoring-based commissioning (MBCx) or Continuous Commissioning (CCx)
For new construction, it’s fairly simple. You need a commissioning agent to sign off on the operation of all the systems in your building in order to get certified for occupancy.
Existing buildings are where commissioning gets more complicated.
What are the different types of commissioning for existing buildings?
Monitoring-based commissioning, continuous commissioning and retro-commissioning are often used interchangeably, but if you aren’t aware of the differences then you run the risk of implementing a costly program that doesn’t deliver the results you’re looking for.
Here are standard definitions of each of the three types of commissioning for existing buildings:
- Retro-commissioning:
- Retro-commissioning is similarly encoded by Congressional law as new construction commissioning in that it requires a licensed commissioning professional when new systems are added to a building post-occupancy.
- In practical applications, retro-commissioning is also used on existing systems that were commissioned during the construction process. For example ASHRAE defines RCx as “the process of making low-cost adjustments to an existing building’s operation to improve its energy performance.”
- Continuous or ongoing commissioning:
- Texas A&M defines continuous commissioning as “an ongoing process to resolve operating problems, improve comfort, and optimize energy use for existing commercial and institutional buildings and central plant facilities.”
- The USGBC via the DOE describes ongoing commissioning as a “process that includes planning, point monitoring, system testing, performance verification, corrective action response, ongoing measurement, and documentation to proactively address operating problems.
- Monitoring-based commissioning:
- The Lawrence Berkeley National Lab defines monitoring-based commissioning as “a way to maintain and continuously improve building performance over time.”
- The Department of Energy encourages the use of MBCx “software tools” for neutral evaluation of energy performance contracts for their ability to collect and analyze real-time operational data across systems over time.
What are the key differences between existing building commissioning options?
Now that we understand the different types of commissioning for existing buildings, let’s explore how they differ from each other in terms of scope and outcomes.
As we started to see in the definitions above, major differences are found at the implementation level. MBCx and continuous or ongoing commissioning are meant to continue over time whereas retro-commissioning is more similar to new building commissioning in that it is a limited project scope that has a defined end date.
Retro-commissioning can be useful when an operational issue is clearly identified and the fix is straightforward enough to call in a contractor, adjust some settings and verify the work completed has solved the problem. The goal is often to restor building operation to design conditions
When you want to support systems operation with data and take targeted actions on problems before they become big enough to require a major system replacement, monitoring-based commissioning or ongoing commissioning are better choices. Typical goals for these commissioning engagements are reductions in energy usage, improvement in occupant comfort or indoor air quality.
Scope and deliverables of commissioning options
In this table, we’ll look at typical scope items and deliverables for the various commissioning options against building optimization as a concept.
| Monitoring-based commissioning | Continuous or ongoing commissioning | Retro-commissioning | Building optimization |
Data connection | X | X |
| X |
Design review |
|
| X | X |
Fault detection and diagnostics | X |
|
| X |
Functional testing |
|
| X | X |
Data normalization and analysis |
|
|
| X |
Documentation and reporting | X | X | X | X |
Real-time data connection to BAS |
|
|
| X |
Measurement & verification | X | X | X | X |
While commissioning activities are important for efficiency programs, often the driver of real change is building optimization. If you’re utilizing commissioning in any form, doing it under the umbrella of building optimization will deliver the most lasting performance improvements. Look for services that include connection to and analysis of BAS data. Prioritize services that provide affordable and ongoing data collection and analysis to augment your engineering team’s capacity to both identify and fix problems. Choose providers who offer a complete package and the reporting to back up their deliverables.
Through our building optimization program – InSite Optimize – we work with clients to review the work of Cx agents and hold them accountable while equipment is under warranty. This gives us unique perspective on the various options available to building owners and property management teams. It’s easy to confuse the different commissioning types and often hard to tell where a commissioning effort ends and an optimization program begins.
About InSite
Founded in 2013, InSite is a leading solution partner for optimization in buildings, extracting value from data to engineer meaningful outcomes for its clients. We deliver financial and operational impact by harnessing our team’s expertise in engineering and building performance optimization. Our Engineered for Results approach combines an intelligence platform that collects and analyzes data for single buildings and entire portfolios with our program management teams who transform data into prescriptive recommendations.
