Introduction
On September 15, 2025, the new VBBL came into effect. From that date, all new Part 3 buildings (larger and more complex buildings such as offices, multi-unit residential, and institutional buildings) in Vancouver have to include commissioning of energy-using systems under the Energy Efficiency section.
Up until September, commissioning has only been mandatory for Part 3 projects that received rezoning approval under the city’s Green Buildings Policy (since 2017) - roughly half of all new Part 3 construction.
The 2025 VBBL closed that gap and extended commissioning requirements to all new Part 3 projects, plus certain work in existing buildings.
In practice, every larger or more complex building will need a defined Cx scope for energy-using systems, a commissioning plan, and formal reporting at key milestones, making structured digital commissioning tools increasingly important.
Retro commissioning
When the commissioning process starts in the operatuon an maintenance phase without prior commissioning.
What is retro commissioning?
Retro commissioning is an after-the-fact commissioning process that helps identify a building's weaknesses and improves its overall performance. This process involves performing an in-depth inspection and analysis of a building's systems and equipment to identify its components, determine their efficiency, and provide recommendations on how to improve the building's overall performance.
What is retro commissioning?
Retro commissioning and commissioning: The differences
There are many differences between retro commissioning (RCx) and standard commissioning (Cx). While they both have similar goals, their processes and implementation can vary.
Commissioning and retro commissioning occur at different times:
Commissioning occurs during building construction or the installation of a new system. This process ensures that the systems are installed to the plan's specifications and work properly and that the building is ready for occupation. Retro-commissioning occurs after a building has been constructed or the equipment has been installed - often years and years.
Due to their nature, Cx and RCx focus on different building components. Cx focuses on the new components installed to ensure they're calibrated and operating according to the design plan. RCx's focus is on improving the performance of the existing building components by identifying operational issues as well as system inefficiencies and deficiencies.
Also, the basis for the two tests is different. For instance, Cx uses the owner's project requirements (OPR) as the goals for the test, and the CxA identifies these early in the process to ensure the building meets those requirements. RCx utilizes current facility requirements (CFR), which are essentially the parameters that the building and its systems should meet to perform at their best.
Reasons for retro-commissioning
There are several reasons why a building owner or operations team would choose to have RCx performed on a building.
The following are some of the most common reasons a building could benefit from RCx:
- Commissioning was never performed when the building was constructed or the system was installed.
- The building has been altered from its original plan, whether building owners upgraded systems, expanded its footprint, the original floor plan has changed, or the original use of the building has changed.
- There are components in the building that have never worked properly.
- Complaints about building comfort or functionality recently increased.
In any of these cases, RCx is typically the best route for assessing the building's current performance and getting it on track to perform efficiently again.
The retro-commissioning process
The new code is an important step toward better-performing, lower-carbon buildings. But it also increases the pressure on commissioning teams. Cx professionals now sit firmly on the critical path at multiple points in the project. A preliminary commissioning report is required before occupancy, and a final report is required at the end of the warranty period. If those deliverables aren’t ready, the project can’t move on.
That raises the bar for process discipline. Cx plans, test forms, issues logs, and reports need to be structured, traceable, and kept current from design through construction and early operation.
For many teams, this new reality will be hard to manage with manual admin alone, and there is growing value in digital commissioning tools - including AI-supported assistants that can take over repetitive documentation and coordination work.
When to implement RCx
Ideally, Cx will be performed during construction. and the ongoing maintenance outlined in the Cx process will sustain the building for years to come. However, it's often the case that facility owners who don't have Cx performed while their buildings are under construction turn to RCx during the operations phase.
RCx has many benefits for these facility owners, as it can help identify deficiencies or inefficiencies and help the building perform at its best. However, it's always better to have Cx performed during the construction phase to catch any issues early and ensure the systems are working efficiently from the start.
Common challenges in the retro commissioning process
While commissioning has its challenges, some challenges are unique to retro commissioning. These challenges are often due to the age of the building, in one way or another.
Aging equipment
Retro commissioning involves older buildings, often with aging equipment. These items can be prone to breaking during RCx, especially if they're being exercised for the first time in many years. Also, finding replacement parts or having to replace a condemned or discontinued unit is another set of challenges frequently faced during RCx.
Lack of plans and documentation
An RCx team needs plans, manuals, and other documentation to perform its duties, but these items are often missing in older buildings. This makes tracking the systems' layouts, identifying components, or understanding system alterations much more difficult than a commissioning project where all the documents are readily available.
Operational incoveniences
By nature, retro commissioning typically occurs in established buildings. As a result, the RCx team will need to enter occupied spaces, inconveniencing typical operations. For example, RCx in a hospital might require shutting down an operating room. Or, RCx in a retail space might require setting up a ladder or lift in an area and cordoning it off from customers.
Lack of access
It's often the case that systems, equipment, and components are hidden over a building's lifetime. While everything is out in the open during a Cx, these items might be hidden behind drywall, above ceilings, or in other areas that might be blocked off. Finding these items can be difficult during RCx and require more time.
The benefits of retro commissioning
Quick payback
According to two meta-analyses performed by E Mills in 2004 and 2009, the amount of time required for a retro commissioning project to pay for itself is just 1.1 years. This is significantly less time than a standard Cx, which takes 4.2 years.
This is not to take away from the Cx process's value but to point out that non-commissioned buildings can significantly benefit from the process.
Energy savings
One of the biggest benefits of retro commissioning is the amount of energy saved by assessing, testing, repairing, replacing, and adjusting poorly-running building equipment.
According to E Mills' study, 25% of commissioned buildings can save up to 30% in energy consumption. Even the lowest 25% can save almost 10% in energy consumption.
Improved equipment lifespan
Putting existing equipment under the microscope and identifying the repairs and maintenance associated will typically result in a longer equipment lifespan.
This reduces the frequency of repair or replacement, further improving savings and preventing unnecessary downtime.
Documentation availability
RCx provides the building owner with a fresh set of documents required for their building. This can include new operations and maintenance manuals, property warranty or service documentation, and ongoing plans and training documents for long-term building use.
This is a significant benefit, especially for buildings with a lack of proper documentation.
Healthier indoor air quality
Improvements in indoor air quality are also a large benefit, especially in older buildings. By addressing IAQ concerns found during the assessment, optimizing the ventilation systems, implementing building air filtration, and controlling humidity levels, RCx teams can significantly improve the quality of air that the building occupants are breathing in.
Choosing the right software for retro commissioning
The new code is an important step toward better-performing, lower-carbon buildings. But it also increases the pressure on commissioning teams.
Cx professionals now sit firmly on the critical path at multiple points in the project. A preliminary commissioning report is required before occupancy, and a final report is required at the end of the warranty period. If those deliverables aren’t ready, the project can’t move on.
That raises the bar for process discipline. Cx plans, test forms, issues logs, and reports need to be structured, traceable, and kept current from design through construction and early operation.
For many teams, this new reality will be hard to manage with manual admin alone, and there is growing value in digital commissioning tools - including AI-supported assistants that can take over repetitive documentation and coordination work.