On this page
- Start with the data before the score
- Site energy: what the building consumes
- Source energy: a broader boundary
- EUI: energy divided by a building characteristic
- Weather-normalized energy
- The ENERGY STAR score
- Cost and emissions answer different questions
- Common failure modes
- From benchmark to action
- If you are comparing a design or code energy model with these benchmarking results or your utility bills, see our guide to why building energy models and actual bills differ.Frequently asked questions
- Sources
Energy benchmarking can show that a building is changing, that it differs from a defined peer group, or that its data deserves investigation. It usually cannot tell you which component failed or which retrofit should be purchased.
The strongest use of a benchmark is to match each metric to a specific question: Is the building using more energy than before? How energy-intensive is it relative to its size? How does it compare with a defined peer group? Are costs or emissions changing?
Start with the data before the score
A polished dashboard can still be built on incomplete information. Before interpreting a trend, verify that all relevant meters are included, the reporting period is complete, units are correct, floor area and occupancy information are current, tenant and common-area loads are handled consistently, and major operating changes are recorded.
ENERGY STAR Portfolio Manager makes more than 100 performance metrics available. That breadth is useful, but it increases the importance of choosing a metric that answers the actual question.
Site energy: what the building consumes
Site energy is the energy used at the property, reflected in the fuels and electricity delivered to it. It is useful for tracking consumption, relating energy use to equipment and schedules, and reconciling bills and meter records. It is not a complete measure of the energy used to produce and deliver electricity or other fuels.
Source energy: a broader boundary
Source energy adds the energy associated with producing and delivering the energy used on site. Portfolio Manager uses source-energy factors to compare fuel types on a common basis. It should not be confused with a utility bill or an on-site meter reading.
EUI: energy divided by a building characteristic
Energy use intensity, or EUI, commonly expresses annual energy use per square foot. It is useful for comparing one building with itself, screening a portfolio and comparing similar buildings when definitions are consistent.
EUI can mislead when the denominator or use is wrong. Mixed-use space, parking, data-heavy areas, vacant floors, unusual hours and changes in floor area can all affect interpretation. A lower EUI is not proof that a building is comfortable, healthy or fully occupied. A higher EUI is not proof that equipment is faulty.
Weather-normalized energy
Weather affects heating and cooling demand. Portfolio Manager provides weather-normalized metrics intended to help users understand performance while accounting for year-to-year weather variation.
Weather normalization is most useful when comparing a building with itself across periods. It does not erase changes in occupancy, schedules, process loads or floor area.
The ENERGY STAR score
For eligible property types, the 1–100 ENERGY STAR score compares modeled performance with a national peer group after accounting for specified operating characteristics.
The score depends on complete inputs, a defined model and an eligible property type. It can identify a building that deserves attention. It cannot tell a technician whether the cause is a schedule, control sequence, envelope condition, ventilation requirement, tenant load or equipment problem.
Cost and emissions answer different questions
Energy cost is affected by rates, demand charges, taxes and tariffs. A falling cost does not necessarily mean falling use. Emissions depend on the accounting method and emissions factors. State whether the number represents direct, indirect, location-based or another defined measure.
Common failure modes
- Partial meter coverage: A missing tenant meter or fuel account can create a false improvement.
- Bad time alignment: Estimated reads or overlapping periods can distort comparisons.
- Incorrect floor area: An old lease or tax record may not match the required denominator.
- Mixed-use simplification: Office, retail, parking and data uses may not fit one assumption.
- Operating changes: Vacancy, longer hours or new electric loads can move the benchmark.
- Diagnosis by benchmark: A benchmark is a screening tool, not a fault detector.
From benchmark to action
- Validate meters, dates, units, areas and use details.
- Compare the right metric with the correct baseline or peer group.
- Explain known operational, occupancy and weather changes.
- Investigate anomalies with interval data, controls trends, bills and observations.
- Audit or commission when system-level diagnosis is required.
- Measure again using the same definitions.
If you are comparing a design or code energy model with these benchmarking results or your utility bills, see our guide to why building energy models and actual bills differ.
Frequently asked questions
Is EUI the same as an ENERGY STAR score?
No. EUI is an intensity metric. The score is a modeled peer comparison for eligible property types.
Does weather normalization show what a building would use in another climate?
Not necessarily. Its primary value is comparing a building across periods with different weather.
Can a benchmark identify a failing rooftop unit?
No. It may reveal an unusual change, but diagnosis requires additional data and investigation.
Should site or source energy be used?
Use the metric that matches the question and label it clearly.
Sources
Accessed October 4, 2026.
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