Siena Court
Multifamily Housing in California, CA · 771 Black Diamond Street, Pittsburg · 94565
At a glance
Siena Court is a 112,736-square-foot multifamily housing building at 771 Black Diamond Street, Pittsburg in Pittsburg, California, built in 2011. In its 2024 California benchmarking disclosure it reported an ENERGY STAR score of 1 out of 100 (grade D), a site energy-use intensity of 153.7 kBtu/ft² and 1,092 tCO₂e of greenhouse-gas emissions. That score is higher than 0% of the 9,612 scored multifamily housing buildings in California.
AB 802 (Public Resources Code §25402.10) · reporting year 2024
Benchmarking record
| Field | Value |
|---|---|
| ENERGY STAR score | 1 (band D) |
| Site EUI | 153.7 kBtu/ft² |
| Source EUI | — |
| GHG emissions | 1,092 tCO₂e |
| GHG intensity | 9.7 kgCO₂e/ft² |
| Electricity | 4,364,663 kWh |
| Natural gas | 19,467 therms |
| Gross floor area | 112,736 sq ft |
| Source record | california:6826589:2024 |
The disclosure history
Year over year
| Year | Score | Δ | Site EUI | GHG emissions |
|---|---|---|---|---|
| 2024latest | 1 | -81 | 153.7 kBtu/ft² | 1,092 tCO₂e |
| 2023 | 82 | +1 | 31.5 kBtu/ft² | 218 tCO₂e |
| 2022 | 81 | +3 | 32.6 kBtu/ft² | 223 tCO₂e |
| 2021 | 78 | -1 | 32.5 kBtu/ft² | 206 tCO₂e |
| 2020 | 79 | -1 | 33.7 kBtu/ft² | 226 tCO₂e |
| 2019 | 80 | 32.3 kBtu/ft² | 223 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
- 771 Black Diamond Street, Pittsburg
- City
- California
- State
- California
- ZIP
- 94565
- Coordinates
- 38.03015, -121.88552
Within ~1 km
Nearby benchmarked buildings
- 2 Marina Boulevard - Ab802score 80
Multifamily Housing · 154,950 sq ft
- Marina Vista Elementary Schoolscore 36
K-12 School · 77,123 sq ft
- Entradascore 88
Multifamily Housing · 56,000 sq ft
See also: most efficient in California · biggest emitters
How does Siena Court compare with other multifamily housing buildings in California?
The latest disclosures cover 10,630 multifamily housing buildings in California, out of 40,029 buildings citywide. Siena Court's ENERGY STAR score of 1 compares with an average of 82 across the 9,612 that report a score; it scores higher than 0% of them and lower than 99%. Its site EUI of 153.7 kBtu/ft² is about 347% above the average of 34.4 kBtu/ft² — it uses more energy per square foot than the typical building in that group. Its emissions intensity of 9.7 kgCO₂e/ft² is about 361% above the group average of 2.1 kgCO₂e/ft².
At 112,736 sq ft, it is about 25% below the average floor area of 150,919 sq ft for those buildings. It was built in 2011, 23 years later than the group's average year built (1988). Across all 24 jurisdictions BuildingCensus covers, the 59,945 multifamily housing buildings average an ENERGY STAR score of 70 and a site EUI of 59.0 kBtu/ft².
How has Siena Court's energy performance changed over time?
BuildingCensus holds 6 California disclosures for Siena Court, covering report years 2019–2024. Its ENERGY STAR score went from 80 in 2019 to 1 in 2024 (-79 points); its best year on file was 2023, at 82. Site EUI moved from 32.3 kBtu/ft² (2019) to 153.7 kBtu/ft² (2024), an 376% increase. Reported emissions went from 223 tCO₂e to 1,092 tCO₂e over the same span (up 389%).
What does an ENERGY STAR score of 1 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: 1 is the bottom of the scale. BuildingCensus bands the score into report-card grades; 1 falls in band D — lowest band (1–54). It sits 74 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. Siena Court's 153.7 kBtu/ft² across 112,736 sq ft works out to about 17.3 billion Btu (5,078 MWh-equivalent) in 2024. The disclosure also reports 4,364,663 kWh of electricity and 19,467 therms of natural gas for the year.
Which law requires Siena Court to report its energy use?
Siena Court 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:6826589:2024). 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 multifamily housing buildings in California
- Shasta Terrace (Sh227)· 112,605 sq ft · score 80 (B)
- Sweeney Lane: 2995 Sweeney Lane· 112,574 sq ft · score 100 (A)
- Oakbrook Manor (Et007)· 112,512 sq ft · score 87 (A)
- Five Points Senior Apartments· 112,500 sq ft · score 94 (A)
- Los Robles De Cortez· 112,452 sq ft
- Cedar Ridge· 112,432 sq ft · score 100 (A)
- Multifamily Housing buildings in California· 10,630 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 Siena Court's energy grade?
Siena Court scores 1 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 Siena Court use?
Its 2024 site energy-use intensity was 153.7 kBtu/ft² across 112,736 sq ft, including 4,364,663 kWh of electricity and 19,467 therms of natural gas.
What are Siena Court's carbon emissions?
Siena Court reported 1,092 tCO₂e of greenhouse-gas emissions (9.7 kgCO₂e/ft²) for 2024.
Where is Siena Court?
Siena Court is at 771 Black Diamond Street, Pittsburg, in Pittsburg, California 94565. Its coordinates are 38.03015, -121.88552 (latitude, longitude), as published in the Building Energy Benchmarking Program (statewide) file.
How big is Siena Court and when was it built?
Siena Court has 112,736 sq ft of gross floor area, as reported in its 2024 disclosure. The disclosure lists 2011 as its year built. It is classed as multifamily housing.
Is Siena Court 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, “Siena Court, Pittsburg, California — 2024 benchmarking disclosure”, https://buildingcensus.com/buildings/california/siena-court-18b9f217 (data as of July 9, 2026).