ASHRAE 90.1-2019 vs. 90.1-2022: The Metering Requirements 

The Evolution of Section 8.4.3: From Basic Metering to Comprehensive Monitoring

ASHRAE 90.1 has incrementally raised the bar on energy metering with each edition. Understanding how the standard has evolved helps engineers design systems that comply not just with today’s code but with the version their jurisdiction will inevitably adopt next.

ASHRAE 90.1-2016 introduced chilled-water plant metering requirements and elevator efficiency provisions. It also added Appendix G as a new compliance path, establishing a fixed baseline that allows buildings from any code version to be compared using a stable metric. These changes signaled ASHRAE’s growing recognition that you cannot manage what you do not measure.

ASHRAE 90.1-2019 took a substantial leap forward. It introduced formal commissioning requirements for any project over 10,000 square feet, with extensive requirements for which commissioning activities must be performed and a mandate that the commissioning provider be independent from the design and construction team. For envelope performance, it required air barriers to be either meticulously inspected for continuity during installation or verified with a whole-building blower door test. Lighting power densities dropped approximately 20 percent from the 2013 edition, reflecting the assumption that all new lighting is LED. Most significantly for metering, 90.1-2019 established that electricity meters must record both consumption (kWh) and demand (kW), that whole-building electricity meters must record power factor, and that all metering data must be recorded at minimum 15-minute intervals and retained for at least 36 months with remote accessibility.

ASHRAE 90.1-2022 expanded the standard’s scope beyond the building itself to include sites, enabling regulation of energy use associated with the building but not physically within it—such as parking lot lighting not connected to the building electrical service, electric vehicle charging stations, and photovoltaic equipment located on-site but not on the building. Section 8.4.3 now requires electrical energy monitoring in all buildings and additions over 25,000 square feet with separate monitoring for whole-building consumption, HVAC systems, interior lighting, exterior lighting, and receptacle circuits. The new Section 11 Energy Credits system requires buildings to achieve a specific number of efficiency credits from a menu of options, and comprehensive energy monitoring is often one of the most straightforward credits to earn. The 2022 edition also introduced a minimum prescriptive requirement for on-site renewable energy and a new Total System Performance Ratio (TSPR) compliance path that evaluates entire HVAC system efficiency rather than individual components.

Where These Standards Are Currently in Effect

The adoption landscape for ASHRAE 90.1 is a patchwork that varies significantly by state and even by city. Here is the current status across the major adopting jurisdictions:

• New Jersey: Adopted ASHRAE 90.1-2019 without amendments for commercial structures in September 2022. This is one of the cleanest adoptions in the country—the full standard, no carve-outs.

• Virginia: Updated its Uniform State Building Code to incorporate ASHRAE 90.1-2019 energy efficiency provisions for commercial buildings, effective January 2024. All buildings with permit applications dated January 18, 2025 or later must comply.

• Michigan: Moving from 90.1-2013 directly to 90.1-2019, skipping the 2016 edition entirely. The state is expected to carve out certain exceptions and customizations, including some electrical metering requirements, though the proposed exceptions have not yet been finalized.

• Connecticut: Incorporated the 2021 IECC (which references 90.1-2019 as an acceptable compliance path) into its state building code in October 2022 without weakening amendments. The state building inspector is now drafting the 2025 state building code incorporating the 2024 IECC.

• Rhode Island: Became the first state in the Northeast to adopt a code based on the 2024 IECC (which references 90.1-2022), effective December 1, 2025. This includes electric-ready provisions for both residential and commercial buildings.

• Colorado: Requires the 2021 IECC as a minimum for any jurisdiction updating its building code between July 2023 and June 2026, with a Low Energy and Carbon Code based on the 2024 IECC required after July 2026.

• Federal Buildings: The Department of Energy set a benchmark that states should adopt 90.1-2022 by January 1, 2028. Federal agencies are required to use the most current standard for new construction.

The trajectory is clear: states that are currently on 90.1-2019 will move to 90.1-2022 within the next two to three years, and the metering requirements will only become more demanding. Engineers who design systems to meet 90.1-2022 today—even if their jurisdiction currently enforces 90.1-2019—save their clients from costly retrofits down the road.

What Subcircuit Monitoring Means for ASHRAE Compliance

Both 90.1-2019 and 90.1-2022 require separate monitoring of energy consumption by end-use category. This cannot be accomplished with a single whole-building meter. It requires subcircuit monitoring—placing sensors on individual circuits or groups of circuits that serve specific equipment types and aggregating that data into the required end-use categories.

The challenge for engineers is that commercial electrical distribution systems are not always designed with metering in mind. A typical panelboard might serve a mix of HVAC, lighting, and receptacle circuits. A main distribution panel might feed sub-panels that combine multiple end-use types. Without subcircuit monitoring, there is no way to separate HVAC consumption from lighting consumption from plug load consumption at the accuracy level the code demands (no more than 5% of the measured load in each category may come from a different category).

How the Panoramic Power Wireless Sensors Solve the Problem

The Panoramic Power sensor family was designed specifically for this challenge. Because each sensor is self-powered, wireless, and physically small (the PAN-10 is roughly the size of a matchbox), sensors can be installed on individual circuit breakers inside any panel without disrupting the building’s electrical operation. There is no need to de-energize circuits, no signal wiring to run through conduit back to a central meter, and no external power connections to provide. An electrician can install hundreds of sensors across an entire building in a single day.

Each sensor is registered in the PowerRadar deployment tool with its unique sensor ID. During the deployment process, the installer maps each sensor to the specific circuit it monitors and assigns it to a device category—RTU-1, AHU-2, Lighting Panel LP-1, Receptacle Panel RP-3, Kitchen Hood Exhaust, Elevator Machine Room, and so on. PowerRadar’s device group feature then allows engineers to aggregate these individual devices into the ASHRAE end-use categories for reporting. For example, RTU-1, AHU-2, Chiller-1, and all pump circuits can be grouped into “Total HVAC,” while LP-1, LP-2, and LP-3 can be grouped into “Interior Lighting.”

This approach provides flexibility that traditional hardwired metering systems cannot match. If a circuit is reassigned from one end-use category to another during a tenant improvement, the sensor does not need to move—only the device group assignment in PowerRadar changes. If new equipment is added, a new sensor can be snapped onto the circuit in minutes and registered in the cloud platform immediately.

The PAN-42 for Three-Phase HVAC Equipment

ASHRAE’s metering requirements place special emphasis on HVAC systems because they typically represent 40–60 percent of a commercial building’s total electrical consumption. For three-phase HVAC equipment—which includes most commercial rooftop units, chillers, cooling towers, and large air handling units—the PAN-42 provides the true power measurement (kW, kVA, kVAR, power factor, kWh) that ASHRAE requires.

The PAN-42 connects to three external current transformers (one per phase) and measures voltage directly from the line. It supports 4-wire Wye (277V/480V), 3-wire Delta (240V/416V), single-phase 3-wire, single-phase 2-wire, and dual-phase configurations—covering every HVAC electrical configuration found in commercial buildings. Data is transmitted wirelessly to the bridge at sub-minute intervals, providing the 15-minute data resolution that ASHRAE 90.1-2019 mandates.

Emergent Metering’s AHU Metering Package ($1,300) bundles a PAN-42 meter, a cellular Gen 4+ Bridge, and appropriately sized current transformers into a single SKU. This turnkey approach reduces specification complexity for engineers, simplifies procurement for contractors, and ensures that all components are compatible and tested together before arriving on site.

The Leviton S7100 BCM for Panelboard-Level Disaggregation

In buildings where the electrical design places many circuits from different end-use categories on a single panelboard, the Leviton S7100 Branch Circuit Monitor provides an efficient alternative to installing individual wireless sensors on every circuit. The S7100 mounts adjacent to the panelboard and uses small CTs on each circuit to simultaneously measure energy across 12, 24, or 48 circuits.

The S7100 communicates via Modbus RTU to an Obvius/Leviton AcquiSuite data hub or directly to the Panoramic Power bridge’s Modbus port. From either path, data flows into PowerRadar, where each circuit can be assigned to the appropriate end-use category. The 48-input model ($3,000) can fully monitor a 42-space panelboard with spare capacity, making it exceptionally cost-effective for mixed-use panels.

PowerRadar as the Unified Front End for ASHRAE Compliance

One of the most common mistakes engineers make when specifying metering systems is creating a fragmented monitoring infrastructure—separate systems for electric metering, gas metering, water metering, and BMS data, each with its own software platform, login credentials, and reporting format. ASHRAE 90.1 requires an integrated data acquisition system that aggregates all energy data into a unified reporting interface. PowerRadar fills this role.

All Panoramic Power wireless sensors, Leviton S7100 BCMs, and pulse-connected third-party meters (gas, water, steam, BTU) feed data into PowerRadar as the single front end. Building operators log into one platform and see their entire energy profile—electric consumption by end-use category, natural gas usage, chilled water and heating water thermal energy, domestic water consumption, and compressed air flow—all in one place. The platform’s automated reporting feature generates the graphical energy reports that both ASHRAE 90.1-2019 and 90.1-2022 require, stored for the mandatory 36-month retention period with remote web and mobile access.

PowerRadar’s data normalization feature allows consumption to be adjusted for weather and other site-specific parameters, enabling fair comparison between buildings in different climate zones or between operating periods with different weather conditions. This is particularly valuable for building owners subject to Building Performance Standards (BPS) that evaluate energy performance against benchmarks. The carbon footprint widget calculates CO2e emissions using configurable emission factors, supporting corporate sustainability reporting alongside code compliance.

For buildings with existing Building Management Systems (BMS), the Honeywell JACE WEB-8000 or WEB-9000 controller provides Niagara Framework protocol translation that can aggregate metering data with BMS operational data—combining energy consumption with HVAC setpoints, occupancy schedules, outdoor air conditions, and control sequences into a comprehensive operational picture. Data from the JACE can be forwarded to PowerRadar for unified reporting, or the JACE can serve as the primary front end for buildings that need deep BMS integration.