Diamond Bar City Hall
Office in California, CA · 21810 Copley Drive, Diamond Bar · 91765
At a glance
Diamond Bar City Hall is a 55,095-square-foot office building at 21810 Copley Drive, Diamond Bar in Diamond Bar, California, built in 1999. In its 2024 California benchmarking disclosure it reported an ENERGY STAR score of 50 out of 100 (grade D), a site energy-use intensity of 55.5 kBtu/ft² and 197 tCO₂e of greenhouse-gas emissions. That score is higher than 16% of the 4,912 scored office buildings in California.
AB 802 (Public Resources Code §25402.10) · reporting year 2024
Benchmarking record
| Field | Value |
|---|---|
| ENERGY STAR score | 50 (band D) |
| Site EUI | 55.5 kBtu/ft² |
| Source EUI | — |
| GHG emissions | 197 tCO₂e |
| GHG intensity | 3.6 kgCO₂e/ft² |
| Electricity | 778,538 kWh |
| Natural gas | 3,974 therms |
| Gross floor area | 55,095 sq ft |
| Source record | california:34663422:2024 |
The disclosure history
Year over year
| Year | Score | Δ | Site EUI | GHG emissions |
|---|---|---|---|---|
| 2024latest | 50 | -4 | 55.5 kBtu/ft² | 197 tCO₂e |
| 2023 | 54 | 52.2 kBtu/ft² | 199 tCO₂e |
Compliance context
AB 802 (Public Resources Code §25402.10)
AB 802 requires every California commercial building over 50,000 sq ft to report energy use to the CEC annually; the CEC publicly discloses the results statewide.
Ownership
No owning organisation shown. Names of private individuals in the disclosure are not published here.
Own or manage this building? Claim it to correct the record and get compliance alerts.
Location
- Address
- 21810 Copley Drive, Diamond Bar
- City
- California
- State
- California
- ZIP
- 91765
- Coordinates
- 33.99919, -117.83079
Within ~1 km
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See also: most efficient in California · biggest emitters
How does Diamond Bar City Hall compare with other office buildings in California?
The latest disclosures cover 6,214 office buildings in California, out of 40,029 buildings citywide. Diamond Bar City Hall's ENERGY STAR score of 50 compares with an average of 75 across the 4,912 that report a score; it scores higher than 16% of them and lower than 84%. Its site EUI of 55.5 kBtu/ft² is roughly in line with the average of 56.4 kBtu/ft² — it uses less energy per square foot than the typical building in that group. Its emissions intensity of 3.6 kgCO₂e/ft² is roughly in line with the group average of 3.6 kgCO₂e/ft².
At 55,095 sq ft, it is about 64% below the average floor area of 151,937 sq ft for those buildings. It was built in 1999, 14 years later than the group's average year built (1985). Across all 24 jurisdictions BuildingCensus covers, the 15,264 office buildings average an ENERGY STAR score of 73 and a site EUI of 59.3 kBtu/ft².
How has Diamond Bar City Hall's energy performance changed over time?
BuildingCensus holds 2 California disclosures for Diamond Bar City Hall, covering report years 2023–2024. Its ENERGY STAR score went from 54 in 2023 to 50 in 2024 (-4 points); its best year on file was 2023, at 54. Site EUI moved from 52.2 kBtu/ft² (2023) to 55.5 kBtu/ft² (2024), an 6% increase. Reported emissions went from 199 tCO₂e to 197 tCO₂e over the same span (down 1%).
What does an ENERGY STAR score of 50 mean?
ENERGY STAR scores run from 1 to 100 and are computed by the EPA's Portfolio Manager as a percentile against similar buildings nationwide, adjusted for climate, size and use: a score of 50 means the building performs better than about 50% of its national peers. BuildingCensus bands the score into report-card grades; 50 falls in band D — lowest band (1–54). It sits 25 points below 75, the threshold for ENERGY STAR certification. In California, 65% of scored buildings are at 75 or above.
Site energy-use intensity (EUI) is the energy a building uses on site in a year divided by its floor area, in thousand Btu per square foot — lower is more efficient. Diamond Bar City Hall's 55.5 kBtu/ft² across 55,095 sq ft works out to about 3.1 billion Btu (896 MWh-equivalent) in 2024. The disclosure also reports 778,538 kWh of electricity and 3,974 therms of natural gas for the year.
Which law requires Diamond Bar City Hall to report its energy use?
Diamond Bar City Hall reports under AB 802 (Public Resources Code §25402.10), the legal basis of California's Building Energy Benchmarking Program (statewide), which publishes each covered building's annual benchmarking results. The record shown here is the report-year 2024 disclosure (source record california:34663422:2024). AB 802 requires every California commercial building over 50,000 sq ft to report energy use to the CEC annually; the CEC publicly discloses the results statewide.
More office buildings in California
- 48710 Kato Road (Child)- Ab802· 55,085 sq ft · EUI 14.2 kBtu/ft²
- 3870 Murphy Canyon Road· 55,018 sq ft · score 88 (A)
- Davis Professional Building· 55,015 sq ft · score 100 (A)
- 1528 S El Camino Real· 55,000 sq ft · score 81 (B)
- Rick Engineering· 55,000 sq ft
- F Street Industrial· 55,000 sq ft
- Office buildings in California· 6,214 benchmarked
- All California benchmarked buildings· AB 802 (Public Resources Code §25402.10)
- Most efficient large buildings in California
- Least efficient large buildings in California
- Biggest emitters in California
Frequently asked questions
What is Diamond Bar City Hall's energy grade?
Diamond Bar City Hall scores 50 out of 100 on ENERGY STAR — band D, lowest band (1–54) — in its 2024 California disclosure. Scores are national percentiles against similar buildings; 75+ qualifies for ENERGY STAR certification.
How much energy does Diamond Bar City Hall use?
Its 2024 site energy-use intensity was 55.5 kBtu/ft² across 55,095 sq ft, including 778,538 kWh of electricity and 3,974 therms of natural gas.
What are Diamond Bar City Hall's carbon emissions?
Diamond Bar City Hall reported 197 tCO₂e of greenhouse-gas emissions (3.6 kgCO₂e/ft²) for 2024.
Where is Diamond Bar City Hall?
Diamond Bar City Hall is at 21810 Copley Drive, Diamond Bar, in Diamond Bar, California 91765. Its coordinates are 33.99919, -117.83079 (latitude, longitude), as published in the Building Energy Benchmarking Program (statewide) file.
How big is Diamond Bar City Hall and when was it built?
Diamond Bar City Hall has 55,095 sq ft of gross floor area, as reported in its 2024 disclosure. The disclosure lists 1999 as its year built. It is classed as office.
Is Diamond Bar City Hall covered by AB 802 (Public Resources Code §25402.10)?
Yes — it appears in the 2024 Building Energy Benchmarking Program (statewide) disclosure, which lists the buildings reporting under AB 802 (Public Resources Code §25402.10).
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About this data
Source: Building Energy Benchmarking Program (statewide) (AB 802 (Public Resources Code §25402.10)), as published July 9, 2026. See the methodology for how records are matched, cleaned and scored.
Cite as: BuildingCensus, “Diamond Bar City Hall, Diamond Bar, California — 2024 benchmarking disclosure”, https://buildingcensus.com/buildings/california/diamond-bar-city-hall-d1720dfe (data as of July 9, 2026).