Monitoring-Based Commissioning (MBCx): The Complete 2026 Guide for Owners and Engineering Firms

Buildings rarely perform as designed, and almost never keep performing as commissioned. Control strategies drift, overrides accumulate, sensors fail silently, and the team that inherits the building inherits problems nobody documented. None of it announces itself. The only evidence is on the energy bill, months later, buried in a number nobody can explain.

Monitoring-based commissioning (MBCx), also called ongoing or continuous commissioning, is the discipline built for that reality. It turns commissioning from a handover event into a permanent feedback loop, so the question "is the building still performing?" gets answered every day instead of once.

This guide is written for the two groups that make MBCx work: the building owners who buy it, and the commissioning agents, engineering consultancies and controls contractors who deliver it. It covers what MBCx is, the software that supports it, what it saves and costs, how US utility programmes, LEED and federal guidance reward it, and how engineering firms turn it into a recurring service.

Key takeaways

• MBCx is a programme, not a project. It combines continuous monitoring, automated fault detection and a verified response loop to hold a building at its commissioned performance.
• Fault detection and diagnostics (FDD) software is the engine. Building analytics and FDD platforms do the continuous checking that makes MBCx affordable at portfolio scale.
• The savings are well documented. Lawrence Berkeley National Laboratory found median electricity savings of 9% and a median payback of 2.5 years across 24 MBCx projects.
• US utilities and LEED pay for it. Several utilities fund MBCx software integration and performance incentives, and LEED awards an extra point for monitoring-based commissioning.
• For engineering firms, MBCx is recurring revenue. Running retro-commissioning first and MBCx permanently after turns one-off projects into retainers.

What is monitoring-based commissioning (MBCx)?

Monitoring-based commissioning (MBCx) is an ongoing commissioning process that uses continuous building data and automated fault detection and diagnostics to keep a building at its commissioned level of performance. Instead of verifying systems once at handover, MBCx checks them every day, flags faults as they develop, and verifies that each fix actually held.

Traditional commissioning verifies design intent at a point in time. MBCx starts from the truth about buildings: they change. Occupancy shifts, someone overrides an economy cycle during a heatwave and never removes it, a temperature sensor drifts out of calibration and takes a chiller schedule with it. Each change is small and reasonable. Together they compound.

You will see the same practice under several names: ongoing commissioning (OCx), continuous commissioning, existing building commissioning and, in utility programmes, monitoring-based or virtual commissioning. The core is always the same: permanent monitoring, analysis against expected behaviour, and a process for acting on what is found.

Traditional commissioning is a project. MBCx is a programme. A project ends; a programme answers, every month, the question a project cannot: is the building still performing?

MBCx vs retro-commissioning

Retro-commissioning (RCx) is a one-time project that brings an existing building back to optimal performance: find the accumulated faults, fix them, re-baseline. MBCx is what stops the building sliding straight back.

The two work best in sequence: RCx recovers the performance, MBCx holds it. For how MBCx compares with commissioning, retro-commissioning and re-commissioning side by side, including costs and US requirements, see Cx vs RCx vs MBCx compared. Many firms now deliver RCx and MBCx as a single continuous engagement, which is quietly reshaping how commissioning services get bought, from projects to retainers. For the practitioner's version of this discussion, our webinar on how FDD improves RCx and MBCx outcomes brings together Aero Performance Group, the Smart Buildings Academy and CIM on exactly this shift.

What tools and software support monitoring-based commissioning?

Monitoring-based commissioning is supported by four types of tool: fault detection and diagnostics (FDD) and building analytics platforms, energy management and information systems (EMIS) for meter data, the building management system's own trend logs, and commissioning workflow software. FDD platforms do most of the work, because they run engineering rules continuously against BMS data.

The US Department of Energy's Federal Energy Management Program describes the same stack in its report on MBCx software tools in performance contracts: software that ties together metering, building automation data and local weather to support ongoing commissioning and identify energy conservation measures. In practice the categories look like this.

Most mature programmes use an FDD platform as the core, fed by the BMS and meters, with work routed into a maintenance system. The FDD platform is the part that changes the economics: it replaces the manual trend-log review that used to consume most of a commissioning budget. For a side-by-side view of how the main platforms differ in type, ownership and fit, see our comparison of FDD and building analytics platforms.

What to require from MBCx software

Six requirements separate a platform that can carry an MBCx programme from a dashboard:

1. BMS-agnostic connection with no forced hardware. It should read Tridium Niagara, Johnson Controls, Siemens, Honeywell, Schneider Electric, Trend and Delta estates as they are. See our BMS integrations page for the systems PEAK supports.
2. Engineered fault rules, not just anomaly flags. Rules built and tuned by mechanical engineers, prioritised by financial and comfort impact, with a credible approach to false positives.
3. Tolerance of imperfect data. Real BMS point lists are inconsistently named and incomplete. Our guide to BMS point naming, Haystack and Brick covers why this decides whether rules scale.
4. A full loop. Task assignment, progress tracking and automated verification that the repair restored normal operation.
5. Evidence for incentive and M&V claims. Utility programmes and performance contracts need savings proven against an adjusted baseline. Our guide to measurement and verification explains the IPMVP and ASHRAE Guideline 14 methods.
6. Multi-client delivery for service firms. Portfolio views across clients, partner-branded reporting, and pricing that scales with the work rather than with headcount.

Why do buildings drift after commissioning?

Buildings drift because small, reasonable changes accumulate unnoticed: manual overrides left in place, setpoints changed after complaints, sensors falling out of calibration and actuators sticking. Because losses arrive gradually, monthly utility bills never show a step change worth investigating, so faults persist for months while the building stays comfortable.

Nobody decides to let a building degrade. It happens one small decision at a time: a manual override during a complaint, a belt that stretches, a damper actuator that sticks at 80% and reads fine from the front end.

The evidence on how far this goes is now solid. Researchers at Lawrence Berkeley National Laboratory analysed multi-year monitoring data from more than 60,000 pieces of HVAC equipment and found that on any given day, 40% of air handling units and 30% of air terminal units were carrying a reported fault, many persisting for more than a fifth of the monitored period (Crowe et al., 2023). Not catastrophic failures: the quiet kind that waste energy, erode comfort and shorten equipment life without ever tripping an alarm. Our analysis of the most common HVAC faults across 600+ monitored buildings shows which fault types dominate in practice.

Drift is especially costly where performance is measured. A building subject to a building performance standard such as NYC Local Law 97, or rated under ENERGY STAR or NABERS, does not announce that it has slipped. The owner finds out at the next reporting cycle, after a year of underperformance is already priced in. One example from CIM's portfolio makes the pattern concrete: real-time anomaly detection that stopped an 8% energy drift caused by manual overrides before it took hold, a fault no alarm would ever have raised.

How does MBCx relate to FDD, the BMS and maintenance software?

FDD is the software that finds and diagnoses faults; MBCx is the programme built around it, with ownership, workflow, verification and review. The BMS controls the building and holds the data, and maintenance software manages the work orders. MBCx connects all three so that each fault is found, fixed and confirmed.

FDD. Fault detection and diagnostics is the engine that makes MBCx continuous rather than periodic. You can run FDD without an MBCx programme (many do, and get a dashboard nobody actions). You cannot run MBCx without FDD.

BMS / BAS. The building management system is the control layer: it runs the building and holds the data. BMS alarms tell you something has broken; MBCx tells you something is wrong even though nothing has broken, which is also why MBCx reduces rather than adds to alarm fatigue.

CMMS and maintenance software. The work management layer tracks work orders and maintenance history. MBCx generates the evidence for the work order and verifies its outcome; the maintenance system manages its execution.

Predictive maintenance. Forecasts when an asset will fail so it can be serviced beforehand. MBCx focuses on what is wrong now, and the same monitoring infrastructure feeds both.

One way practitioners frame the analytics behind a mature programme is as five questions, asked in rising order of ambition: is it operating as intended, how well is it operating, how can we make it better, can we spot issues early, and what happened when something went wrong. Fault detection answers the first. A programme that lasts grows into all five.

What does a monitoring-based commissioning programme include?

A real MBCx programme has three components: an analytics layer that connects to the BMS and meters, fault-detection rules that compare actual behaviour with expected behaviour, and a response loop that assigns each fault, tracks the work and verifies the fix in the data. Without the third component, MBCx becomes a monthly report nobody acts on.

1. The analytics layer. A platform that connects to the existing BMS (whoever made it), utility meters and any additional sensors, normalises that data, and runs FDD rules against it continuously. An MBCx programme that starts with a hardware retrofit is a programme that starts next financial year.

2. The fault-detection intelligence. Rules that compare actual behaviour against expected behaviour: chillers running out of hours, simultaneous heating and cooling, economy cycles that never engage, sensors reporting the physically impossible. Quality matters more than quantity: badly tuned rules bury teams in false positives, and a team that has learned to ignore alerts has an expensive screensaver, not a commissioning programme.

3. The response loop. Detection has to flow into assignment, assignment into work, and work into verification that the fix actually held, timestamped in the data. That verification step is also what makes commissioning honest. The party verifying performance should not be the party whose work is being verified. An independent monitoring layer referees the loop for everyone: the owner sees verified outcomes, and good contractors get data that proves their work. In CIM's own ticket data, about 1 in 6 sampled closures were made before the building data confirmed the fix, which we cover in how to verify a contractor actually fixed an HVAC fault.

What does an MBCx programme find?

MBCx findings fall into two groups. Corrective measures fix what is wrong, such as leaking valves, miscalibrated airflow stations and faulty economiser operation. Improvement measures make the building run better than it did on day one, such as reset sequences, demand control ventilation and schedules matched to actual occupancy.

Corrective measures include terminal units reheating above the reheat setpoint, airflow stations out of calibration, improper economiser operation, valves leaking through when commanded closed, minimum airflow fractions out of calibration, and excessive cycling. LBNL's benchmarking of 24 MBCx projects found deficiencies most often in HVAC equipment (65% of sites) and air-handling and distribution systems (59%), followed by cooling plants, heating plants and terminal units.

Improvement measures include temperature and pressure reset sequences, identifying critical zones and using them to tune sequences and setpoints, demand control ventilation, and schedules matched to actual occupancy. They tend to arrive later, once the corrective backlog is under control, and they are why a good programme is still finding value in year three.

When a finding needs a contractor, the next question is who pays. Our guide to costing remedial works from FDD sets out which faults are already covered by planned maintenance and which are chargeable.

How much does monitoring-based commissioning save, and what does it cost?

Lawrence Berkeley National Laboratory's benchmarking of 24 MBCx projects found median electricity savings of 9%, a median cost of $1.00 per square foot and a median simple payback of 2.5 years. A later LBNL survey of 550 buildings running fault detection found median energy savings of 8%.

The evidence base comes from three LBNL studies, each looking at a different slice of practice:

The studies span more than a decade and different mixes of software and labour, so treat them as a range rather than a forecast. The consistent finding is that savings are real, payback is short, and results vary most with how well-optimised the building was to start. How savings like these are proven rather than estimated is set out in our guide to measurement and verification.

Energy is the easiest benefit to quantify, but rarely the only one that matters:

Compliance and ratings. Building performance standards, ENERGY STAR scores and operational ratings are calculated from measured consumption, so drift caught in week two rather than at the annual reporting cycle protects the result.

Maintenance efficiency. Technicians arrive knowing what is wrong instead of diagnosing on site, and faults are addressed while they are cheap, in a scheduled window rather than an emergency call-out.

Asset life. Short cycling, hunting and running outside design conditions all shorten equipment life. Removing them defers capital replacement, and equipment that keeps flagging is telling you something about its remaining life.

Contractor accountability. Continuous monitoring makes it visible whether work was completed and whether it worked. For good contractors that is an upgrade, not a threat.

Which US utility programmes pay for monitoring-based commissioning?

Several US utilities fund MBCx directly, typically by paying part of the cost of integrating monitoring software with the building automation system and then paying performance incentives on verified savings. Programmes run by Salt River Project, Puget Sound Energy, ComEd and Seattle City Light are examples, and New York has run market-building programmes.

Programme designs differ, but they share a structure: an eligibility threshold based on building size or consumption, an integration or implementation incentive, and one or more performance incentives tied to measured savings. A few current examples:

• Salt River Project (Arizona). SRP's retrocommissioning programme offers an MBCx path for facilities over 150,000 sq ft or 3 million kWh a year. MBCx customers receive 50% of the cost of integrating monitoring software and hardware, up to $15,000, and a further 50%, up to $15,000, on successful completion, on top of savings-based rebates.
• Puget Sound Energy (Washington). PSE's MBCx programme pays an implementation incentive once the commissioning process is in place, then first- and second-year performance incentives, and uses quarterly reporting to keep savings on track.
• ComEd (Illinois). ComEd runs retro-commissioning, monitoring-based and virtual commissioning paths for different building sizes; ACEEE cites it as an example of a multipronged utility approach to MBCx.
• Seattle City Light (Washington). Its monitoring-based commissioning incentive requires the FDD software to track resolved faults over time, not just detection.
• New York. ACEEE reports that a New York State programme found total MBCx costs of about $1 per sq ft, with the programme paying about 25%.

Two practical points follow for anyone building an incentive claim. First, terms change every programme year, so always check the current programme manual before scoping. Second, the evidence requirement is rising: programmes increasingly want resolved faults and measured savings, not a list of findings. A platform that verifies fixes and holds an adjusted baseline produces most of that evidence pack as a by-product of running the programme.

How do LEED, federal guidance and building performance standards treat MBCx?

LEED v4 and v4.1 award an extra point for monitoring-based commissioning under the Enhanced Commissioning credit. The Federal Energy Management Program recommends building MBCx into energy savings performance contracts. Building performance standards measure ongoing operational performance, which MBCx exists to protect.

LEED. Under the LEED v4 and v4.1 Building Design and Construction Enhanced Commissioning credit, Option 1 Path 1 (Enhanced Commissioning) earns 3 points. Path 2 (Enhanced and Monitoring-Based Commissioning) earns 4, and requires monitoring-based procedures in the commissioning plan, including the measurement requirements, the points to be tracked, and the frequency and duration of trend monitoring. For Commercial Interiors projects, the monitoring-based option is worth 5 points.

Federal Energy Management Program (FEMP). FEMP's 2021 report recommends integrating MBCx software into energy savings performance contracts (ESPCs) and utility energy service contracts (UESCs), and explains how it supports each contract phase, from identifying conservation measures to measurement and verification. FEMP notes that MBCx remains underused in performance contracts.

ASHRAE. ASHRAE Standard 202 and Guideline 0 define the commissioning process itself, and Guideline 0.2 extends it to existing buildings. MBCx is how that process continues after handover rather than ending at it.

Local laws and performance standards. NYC Local Law 87 requires periodic retro-commissioning of large buildings, and performance standards such as Local Law 97, Boston's BERDO and Washington State's Clean Buildings Act set limits that buildings must meet year after year. A one-off retro-commissioning study can get a building compliant; MBCx is how it stays compliant.

How do engineering firms deliver MBCx as a service?

Most engineering firms deliver MBCx as a recurring retainer that follows a retro-commissioning project. The firm runs an FDD platform across the client's buildings, triages and verifies faults, coordinates fixes with contractors, and reports verified savings each quarter. The platform does the routine checking, so one engineer can cover many more sites.

For commissioning agents, engineering consultancies and controls contractors, MBCx changes the business model more than the engineering. Four things decide whether it works commercially.

1. Sell the sequence, not the project. RCx recovers performance; MBCx holds it. Selling the two as one engagement turns a 12 to 18 month project into a standing service. Our guide to how engineering firms run RCx, MBCx and data-driven maintenance on FDD walks through the delivery model in detail.

2. Make the renewal case write itself. A Building Commissioning Association market survey put the industry's MBCx contract renewal rate at roughly 10%, usually because year two arrives with an invoice and no new story. The document that renews a contract is short: verified savings to date, actions closed and in flight, comfort trend against target, and compliance position re-estimated from metered data.

3. Line the programme up with incentives. Where a utility programme exists, design the monitoring scope, baseline and reporting cadence around its requirements from day one, so the incentive claim is assembled as the work happens rather than reconstructed at the end.

4. Let software carry the checking. Manual MBCx scales by hiring; system-driven MBCx scales by software. A no-code rules engine also lets a firm capture its best engineer's diagnostic logic as rules that run on every site.

How the platform is priced matters too. CIM licenses PEAK to engineering and service partners per data point, so the platform cost scales with the size of each client's building and can be built into the firm's own pricing. Direct customers are licensed per square metre of floor area. We have written about how to weigh platform choices, including what to be sceptical of, in partner, tool or competitor: how engineering firms should choose a building analytics platform.

What it looks like in practice

Aero Performance Group, a Chicago-based division of the Hill Group, runs its RCx and MBCx client portfolio on PEAK. Since adopting it, Aero has grown its active project portfolio by 50% without adding resources, and more of its fixed-term projects now extend into longer-term engagements. Daniel Hosko, Commissioning Manager at Aero, says PEAK has "enabled us to identify energy-saving opportunities more efficiently while providing our clients unmatched visibility into their building performance."

How do you implement monitoring-based commissioning?

Implementing MBCx takes six steps: define goals and scope, baseline current performance, integrate BMS and meter data, tune the fault detection to the building, set up the response and verification process, and review results on a fixed cadence. Data integration and rule tuning decide how quickly the programme earns trust.

1. Define goals and scope. Energy intensity, compliance with a performance standard, comfort complaint reduction, maintenance cost: pick the metric that matters and let it drive which assets go first. Buildings with known issues, high energy intensity or an approaching compliance deadline are natural starting points.

2. Baseline current performance. Document how systems actually run today, not design intent. The baseline is the reference that makes both improvement and drift measurable, and the foundation of any incentive or M&V claim.

3. Integrate the data. Connect BMS points, meters and weather feeds into one normalised dataset. This is where timelines blow out on most platforms, through months of manual point-mapping. Machine-learning-assisted tagging compresses it to weeks; ask any vendor for their median contract-to-live time.

4. Tune the fault detection. Thresholds calibrated to the actual building, not the design manual. The same rule needs different tuning in a hospital in Phoenix and an office tower in Chicago, and the first month of tuning determines whether the team trusts the system in month six.

5. Establish the response process. Who triages alerts, who assigns, how contractors receive and close work, what the escalation path is, and how fixes are verified in the data. Write it down and train everyone.

6. Review and compound. Monthly or quarterly reviews of open faults, resolution rates and performance trends, with findings fed into capital planning and contractor reviews.

Why do MBCx programmes fail?

MBCx programmes usually fail for organisational rather than technical reasons: nobody owns the fault list, alerts are badly tuned and get ignored, fixes are never verified, or messy data is not cleaned up at onboarding. Naming an owner before go-live and tuning hard in the first weeks prevents most failures.

Messy data. Point names that match no documentation, uncalibrated sensors, gaps when systems drop offline. Fix it systematically at onboarding, validating the critical points first, rather than discovering it fault by fault.

Alert fatigue. Start with high-impact rules only, tune hard in the first weeks, expand as trust builds. An ignored alert system is worse than none, because it manufactures false confidence.

Nobody owns the list. Faults arrive, nobody owns triage, the list grows, people stop looking. Name the owner before go-live.

Skipping verification. Without confirming faults cleared in the data, you cannot distinguish a working programme from an ignored one, and savings claims rest on assumption.

Organisational resistance. Contractors fear the accountability; site staff fear the implication. The honest answer is that the data helps good operators and exposes only the other kind. Lead with quick wins that make the site team look good, and bring contractors in as participants in the loop, not subjects of it.

Where CIM's PEAK Platform fits

PEAK was built as the continuous layer this guide describes. It connects to existing BMS estates with no new hardware, onboards buildings in weeks using machine-learning-assisted tagging, runs engineer-built FDD rules tuned per building, and closes the loop from alert through assignment to verified resolution. Every customer gets a dedicated engineer with mechanical or mechatronic qualifications.

CIM monitors more than 600 commercial buildings in 11 countries, covering more than 100 million square feet, with average energy savings of 19% per asset. More than 20 engineering partners deliver RCx, MBCx and data-driven maintenance on the platform, licensed per data point so the platform cost scales with each engagement. CIM is fully independent: it is not owned by, or affiliated with, any equipment, controls or BMS manufacturer, which is what lets owners, service providers and engineers all trust the same record. For quick answers on pricing model, integrations and security, see the CIM and PEAK FAQ.

Frequently asked questions

What is monitoring-based commissioning?

Monitoring-based commissioning (MBCx) is an ongoing commissioning process that uses continuous building data and automated fault detection and diagnostics to keep a building at its commissioned performance. It checks systems every day rather than once at handover, flags faults as they develop and verifies that each fix actually held.

What is the difference between MBCx and retro-commissioning?

Retro-commissioning is a one-time project that restores an existing building to optimal performance. MBCx is the ongoing programme that keeps it there, catching new faults as they develop. The strongest results come from running retro-commissioning first and MBCx permanently afterwards, often as one continuous engagement.

What is the difference between MBCx and FDD?

Fault detection and diagnostics (FDD) is the software that finds and diagnoses faults automatically. MBCx is the programme built around it: ownership, response workflow, verification and regular review. FDD without MBCx produces a list nobody works; MBCx without FDD is too labour-intensive to run at scale.

What software is used for monitoring-based commissioning?

MBCx relies mainly on fault detection and diagnostics and building analytics platforms, such as CIM PEAK, Clockworks Analytics, CopperTree Kaizen and SkySpark, which run rules continuously against BMS data. Energy management and information systems track metered consumption, and commissioning workflow tools manage plans and issues logs.

How much energy does MBCx save?

Lawrence Berkeley National Laboratory's benchmarking of 24 MBCx projects found median electricity savings of 9%, with a range of 1% to 17%. A later LBNL survey of 550 buildings running fault detection found median energy savings of 8%. Results vary most with how well-optimised the building was to start.

How much does monitoring-based commissioning cost?

In LBNL's benchmarking of 24 MBCx projects, the median cost was $1.00 per square foot, with a median simple payback of 2.5 years. LBNL's Smart Energy Analytics Campaign found median software costs of $0.03 per square foot to install and $0.02 per square foot a year. Utility incentives can offset part of the cost.

Do US utilities offer incentives for MBCx?

Yes. Several utilities fund MBCx, typically by paying part of the cost of integrating monitoring software and then paying performance incentives on verified savings. Salt River Project, Puget Sound Energy, ComEd and Seattle City Light run MBCx paths. Terms change each programme year, so check the current programme manual.

Does LEED give credit for monitoring-based commissioning?

Yes. Under the LEED v4 and v4.1 Building Design and Construction Enhanced Commissioning credit, Enhanced Commissioning earns 3 points and Enhanced and Monitoring-Based Commissioning earns 4. The monitoring path requires procedures in the commissioning plan covering the points to be tracked and the frequency and duration of trend monitoring.

How long does MBCx implementation take?

With machine-learning-assisted point tagging and no new hardware, onboarding typically takes weeks rather than months, with the first fault rules live within about 30 days of starting integration. Full tuning and bedding in the response workflow usually takes a few months more.

Does MBCx require new sensors?

Usually not. Modern platforms read data from the existing BMS, meters and sensor networks. Targeted additions such as valve position feedback or sub-metering on major plant can sharpen specific monitoring later, but they are an optimisation rather than a prerequisite.

How do engineering firms charge for MBCx?

Most firms charge a recurring retainer for MBCx, usually following a retro-commissioning project, and report verified savings, closed actions and comfort trends each quarter. The analytics platform is a cost of delivery; CIM licenses PEAK to engineering partners per data point, so it scales with each client's building.

How does MBCx change the contractor relationship?

Work shifts from calendar-based inspections to responses to specific, evidenced faults, and resolution becomes measurable. For good contractors that is an upgrade rather than a threat: verified performance data proves the value of their work in a way a service report never could.