ASHRAE 90.1 energy monitoring, met and kept running
ASHRAE 90.1 is the US energy standard for buildings other than low-rise residential, adopted through state codes. Its section 8.4.3 requires new buildings of 25,000 sq ft or more to meter energy by end use and keep the data. Aqueduct is that metering and record.
Who it applies to
The standard covers commercial buildings, multifamily buildings over three stories and hotels of any height. It reaches owners through state energy codes: under federal law each state must certify that its commercial code meets the edition the Department of Energy has affirmed, currently 90.1-2022.
Chapters set requirements for the envelope (5), HVAC (6), service water heating (7), power (8) and lighting (9). Most are design rules checked at permit. Section 8.4.3 is different: it requires metering that has to keep working after handover.
What electrical energy monitoring requires
Clause numbers follow 90.1-2022 as amended by Addendum br (2025). Your code official decides compliance.
| Requirement | What it asks for | Data Aqueduct supplies |
|---|---|---|
| 8.4.3.1, monitoring | Separate measurement of total electricity, HVAC, interior lighting, exterior lighting, receptacles and refrigeration. | Sub-meters or CT clamps per category, mapped to panels in aQ Core. |
| 8.4.3.1, tenants | In tenant buildings, the same categories measured per tenant. | Meters assigned to each tenancy, with its own dashboard and export. |
| 8.4.3.2, recording | Data recorded at least every 15 minutes. | Interval readings stored at 15 minutes or finer. |
| 8.4.3.2, reporting | Reports at least hourly, daily, monthly and annually, shared with each tenant. | Hourly to annual reports per category and tenant. |
| 8.4.3.2, retention | All data kept for at least 36 months. | Full interval history retained and exportable. |
Numbers that matter
Site energy savings DOE found for 90.1-2022 over the 2019 edition.
Source: DOE determination, Federal Register 2024Deadline for states to certify codes against 90.1-2022.
Source: DOE determination, Federal Register 2024The 2025 edition is published, adding graphical display of energy data where direct digital controls exist. A DOE determination is pending.
Source: ASHRAERelated standards
sites in 21 countries run on Aqueduct.
and 9 clinics in one of India’s top hospital chains.
US airport running water intelligence on Aqueduct.
of commercial real estate under Aqueduct.
FMCG manufacturing campus.
operations run on Aqueduct.
Related
Common questions
Buildings under 25,000 sq ft, tenant spaces under 10,000 sq ft, dwelling units and hospital critical and life-safety branches. A category under a tenth of the building load may be combined with another, and Aqueduct can still meter exempt spaces where the owner wants the data.
Mainly through alterations and additions, which must meet the code in force for the work being done. Ongoing operation is not policed by the standard itself, which is why metering often stops being read after handover.
The one your state or city has adopted, which may lag the latest ASHRAE edition by several years. Local amendments can also change the metering section, so confirm the edition and any amendments with the authority having jurisdiction before metering is designed.
At least 36 months under section 8.4.3.2. Aqueduct keeps the full interval history beyond that minimum, so a tenant question or an audit three years on can still be answered from the original readings rather than from summary reports. See load disaggregation.
See Aqueduct on your own facility.
Bring a site, a utility bill or a question. We will show you where the loss is.