Monitoring-Based Commissioning, often called MBCx, is a data-driven process that continuously monitors building systems, analyzes performance, identifies operational issues, and helps facility teams correct problems before they become expensive.
Instead of commissioning a building once and hoping performance holds, MBCx uses ongoing trend data, energy analytics, building automation system information, fault detection, and verification methods to keep HVAC and related systems operating as intended over time.The U.S. Department of Energy describes ongoing commissioning as a process that includes planning, point monitoring, system testing, performance verification, corrective action response, measurement, and documentation to proactively address building operating problems. Monitoring-based commissioning is one of the key approaches used for this ongoing process. [energy.gov]
Modern commissioning standards reinforce this shift toward continuity. ASHRAE/IES Standard 202-2024 frames commissioning as a lifecycle activity that begins at a building's inception and continues to support successful performance through training, documentation, and ongoing verification — not a process that ends at turnover.
For property managers, chief engineers, facility directors, and healthcare facility teams, MBCx helps answer a simple question:
Is the building actually performing the way it is supposed to perform today?
In many buildings, the answer changes over time.
Schedules drift. Sensors fall out of calibration. Control sequences get overridden. Dampers stick. Valves leak by. Tenants change. Occupancy patterns shift. Equipment is repaired, replaced, or adjusted. The building that performed well after a commissioning project can slowly become inefficient, uncomfortable, or unreliable.
Monitoring-based commissioning is designed to catch that drift.
Commercial buildings are full of systems that depend on timing, controls, sensors, airflow, water flow, pressure relationships, temperature setpoints, and equipment sequencing. When one piece falls out of alignment, the building may still "work," but it may be wasting energy, creating comfort complaints, or hiding mechanical issues.
MBCx helps facility teams move from reactive troubleshooting to proactive performance management.
Common issues found through monitoring-based commissioning include:
Lawrence Berkeley National Laboratory describes MBCx as a way to maintain and continuously improve building performance over time, often using tools such as fault detection and diagnostics, energy information systems, and building automation system trend logs. [bies.lbl.gov]
That distinction matters. MBCx is not just a dashboard. It is a process.
A dashboard can show data. MBCx turns that data into verified operational improvements.
A successful MBCx process usually includes five core steps.
Before improvements can be made, the facility team needs to understand how the building is currently operating. This includes reviewing utility data, BAS trends, equipment schedules, setpoints, sequence of operations, comfort complaints, maintenance history, and prior commissioning or TAB reports.
The goal is to answer:
For large or complex facilities, the first focus is often HVAC, central plant equipment, air handling systems, critical spaces, and high-energy-use areas.
MBCx relies on data from systems such as:
The Better Buildings Solution Center notes that an MBCx plan helps define the process, roles, responsibilities, monitoring approach, and use of energy management information systems for ongoing analytics. [betterbuildings.energy.gov]
This planning step is important because more data does not automatically create better performance. The right data needs to be collected, reviewed, prioritized, and acted on.
Once data is collected, the commissioning team reviews trends and analytics to identify performance issues. Some findings may come from automated fault detection. Others require engineering review and field validation.
Examples include:
This is where MBCx separates itself from simple energy reporting. The goal is not only to see that energy use increased. The goal is to find out why.
After issues are identified, the facility team or commissioning provider develops corrective actions. These may include:
Many MBCx improvements are operational and low-cost compared to major capital projects. That is one reason the process can be attractive for property managers looking for measurable improvements without immediately replacing equipment.
The final step is verification. The team confirms that the corrective action worked and that the issue did not return.
This may include:
The Department of Energy notes that continuous monitoring can help identify equipment inefficiencies as they occur, allowing for faster remediation and greater energy and cost savings. [energy.gov]
That is the point of MBCx. It keeps looking.
Monitoring-based commissioning and retro-commissioning are related, but they are not the same.
| Retro-Commissioning (RCx) | Monitoring-Based Commissioning (MBCx) | |
|---|---|---|
| Structure | Project-based, with a defined start and end | Ongoing process with no fixed end date |
| Primary goal | Find and fix existing deficiencies | Maintain performance and catch new drift |
| Data approach | Point-in-time investigation and testing | Continuous data collection and analysis |
| Typical trigger | Comfort complaints, high energy use, or a one-time audit | Desire for persistent savings and ongoing visibility |
| Tools used | Functional testing, TAB reports, field investigation | BAS trend data, fault detection and diagnostics (FDD), energy information systems |
| Outcome | A corrected, re-commissioned building at project close | A continuous loop of detection, correction, and verification |
| Best used | After a building has known or suspected operational problems | After RCx, or for buildings that need sustained performance assurance |
A practical way to think about it:
The Department of Energy identifies monitoring-based commissioning as one approach within ongoing commissioning for existing buildings. [energy.gov]
For many buildings, the best path is not choosing one or the other. It uses RCx to correct known deficiencies, then MBCx to maintain performance.
MBCx can be applied to many building systems, but the greatest value is often found in systems with high energy use, operational complexity, or comfort sensitivity.
HVAC is usually the first focus because it is often one of the largest energy users in commercial buildings. MBCx can help optimize air handlers, rooftop units, VAV systems, chilled water systems, hot water systems, pumps, fans, economizers, and control sequences.
Chillers, boilers, cooling towers, pumps, and heat exchangers benefit from continuous monitoring because small inefficiencies can create significant energy waste.
Healthcare, laboratory, cleanroom, pharmaceutical, and other controlled environments require tighter management of pressure, airflow, temperature, humidity, filtration, and ventilation. In these spaces, MBCx can support performance, compliance readiness, and operational awareness.
Office buildings often experience changes in occupancy, tenant schedules, after-hours use, and space configurations. MBCx helps align system operation with actual building use.
USGBC includes monitoring-based commissioning as part of enhanced commissioning pathways, and describes it as a method that provides building owners, operators, and commissioning authorities with a continual stream of information to identify operational issues as they occur. [usgbc.org]
MBCx helps identify waste that may not be visible during routine building operation. Examples include unnecessary runtime, simultaneous heating and cooling, improper economizer operation, and reset strategies that are not working.
ACEEE reported that monitored commissioning programs showed average energy and peak demand savings of approximately 9 percent across reviewed programs. [aceee.org]
Comfort complaints often come from hidden system issues. MBCx helps identify temperature control problems, airflow issues, scheduling problems, and control instability before they become recurring complaints.
When systems operate outside intended parameters, equipment can experience additional wear. MBCx helps identify short cycling, excessive runtime, valve leakage, pressure problems, and control issues that can shorten equipment life.
MBCx gives operators a clearer view of how the building is actually performing. This helps prioritize maintenance, capital planning, and corrective actions.
Performance improvements can fade over time if no one is monitoring them. MBCx helps maintain savings by detecting system drift and performance degradation.
The Department of Energy identifies energy savings persistence, improved measurement and verification, and better O&M prioritization as key benefits of using monitoring-based commissioning in performance contracts. [energy.gov]
A good MBCx process creates a record of findings, actions, verification steps, and performance trends. This documentation is useful for property managers, engineers, ownership groups, capital planning teams, and compliance-focused facilities.
MBCx is especially valuable for large, complex, or energy-intensive buildings, but it is not limited to them.
Buildings that are strong candidates for MBCx usually have:
ACEEE found that many programs focus on buildings larger than 50,000 square feet with existing building energy management systems, although simplified approaches can also work for smaller buildings and portfolios. [aceee.org]
For smaller buildings, the scope may be narrower. Instead of full-building analytics, the process may focus on schedules, energy trends, rooftop units, BAS alarms, and key comfort or energy issues.
The cost of MBCx depends on building size, system complexity, analytics software, metering needs, BAS readiness, commissioning scope, and the level of engineering review required.
The bigger question is usually not "What does MBCx cost?"
It is:
What is the building currently spending because no one is catching operational waste?
Energy waste, comfort complaints, emergency repairs, overtime troubleshooting, premature equipment wear, and recurring control issues all carry a cost.
ACEEE noted that one study found an average simple payback period of about two years for MBCx, with average energy and peak demand savings near 9 percent across reviewed programs. [aceee.org]
Actual results vary, and not every building will produce the same return. The best candidates are buildings where the operating team is willing to implement corrective actions and verify results. Utility incentive programs, covered below, can also meaningfully shorten that payback period.
Many utilities now offer financial incentives specifically for MBCx programs, which can significantly offset the cost of software, metering, and ongoing services.
Examples of how these programs typically work:
Programs and eligibility criteria vary significantly by utility, region, and building type. Property managers and facility directors should check with their local electric or gas utility, or a regional energy efficiency program, to confirm current incentive availability, funding caps, and qualification requirements before scoping an MBCx project. Building incentive eligibility into the MBCx plan early — rather than as an afterthought — also makes the reporting and verification requirements easier to satisfy.
The best data points depend on the building, but common MBCx trend points include:
In critical environments, additional monitoring may include room pressure, air change rates, exhaust system performance, humidity control, temperature stability, and ventilation compliance indicators.
The point is not to trend everything forever. The point is to trend the right points and review them with enough context to make decisions.
MBCx can fail when it becomes software without ownership.
A building can have years of trend data and still operate poorly if no one is analyzing the information.
Fault detection tools are useful, but they do not replace engineering judgment, field verification, or knowledge of how the building is supposed to operate.
Many building issues come from sequences that are outdated, poorly written, overridden, or no longer aligned with current use.
Closing a work order is not the same as confirming the system now performs correctly.
Chief engineers and facility teams understand how the building behaves day to day. Their input is critical to identifying practical, durable solutions.
MBCx works best as an ongoing process. If monitoring stops, performance drift can return.
A practical MBCx rollout can start with a focused approach.
Start with systems that have the greatest impact on energy, comfort, risk, or compliance.
Determine what data already exists in the BAS, meters, utility bills, prior reports, and maintenance records.
Bad data leads to bad decisions. Confirm that key sensors and meters are accurate enough to support analysis.
Goals may include reducing energy use, improving comfort, stabilizing critical environments, reducing runtime, improving central plant performance, or supporting sustainability reporting.
The plan should define systems, trend points, review frequency, responsibilities, reporting, corrective action workflow, and verification methods.
The value of MBCx comes from the loop: find issues, fix issues, verify results, and keep monitoring.
Monitoring-based commissioning gives building teams a better way to manage performance. It does not depend on guesswork, annual walkthroughs, or waiting for complaints. It uses real operating data to identify problems, prioritize corrective actions, and verify that improvements actually worked.
For property managers and chief engineers, the value is simple: fewer surprises, better visibility, lower waste, and a building that stays closer to its intended performance.
A building does not stay optimized on its own. MBCx gives the team a process to keep it there.