Bluestone Apts
Multifamily Housing in Seattle, WA · 9051 20TH AVE SW · 98106
At a glance
Bluestone Apts is a 51,521-square-foot multifamily housing building at 9051 20TH AVE SW in Seattle, Washington, built in 2017. In its 2025 Seattle benchmarking disclosure it reported an ENERGY STAR score of 81 out of 100 (grade B), a site energy-use intensity of 23.5 kBtu/ft² and 7 tCO₂e of greenhouse-gas emissions. That score is higher than 31% of the 1,652 scored multifamily housing buildings in Seattle.
Seattle Energy Benchmarking Ordinance (SMC 22.920) · reporting year 2025
Benchmarking record
| Field | Value |
|---|---|
| ENERGY STAR score | 81 (band B) |
| Site EUI | 23.5 kBtu/ft² |
| Source EUI | 65.9 kBtu/ft² |
| GHG emissions | 7 tCO₂e |
| GHG intensity | 0.1 kgCO₂e/ft² |
| Electricity | 355,124 kWh |
| Gross floor area | 51,521 sq ft |
| Source record | seattle:50312:2025 |
The disclosure history
Year over year
| Year | Score | Δ | Site EUI | GHG emissions |
|---|---|---|---|---|
| 2025latest | 81 | +3 | 23.5 kBtu/ft² | 7 tCO₂e |
| 2024 | 78 | ±0 | 24.0 kBtu/ft² | 7 tCO₂e |
| 2023 | 78 | +5 | 24.5 kBtu/ft² | 7 tCO₂e |
| 2022 | 73 | -7 | 26.4 kBtu/ft² | 8 tCO₂e |
| 2021 | 80 | +10 | 24.4 kBtu/ft² | 7 tCO₂e |
| 2020 | 70 | -5 | 25.2 kBtu/ft² | 8 tCO₂e |
| 2019 | 75 | -12 | 24.5 kBtu/ft² | 7 tCO₂e |
| 2018 | 87 | 21.8 kBtu/ft² | 7 tCO₂e |
Compliance context
Seattle Energy Benchmarking Ordinance (SMC 22.920)
Seattle's Building Emissions Performance Standard (adopted 2023) applies to buildings over 20,000 sq ft: benchmarking verification is due 2027–2030 and initial emissions targets 2031–2035, reaching net zero by 2041–2050, with fines for non-compliance.
Ownership
No owning organisation shown. Names of private individuals in the disclosure are not published here.
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Location
- Address
- 9051 20TH AVE SW
- City
- Seattle
- State
- Washington
- ZIP
- 98106
- Coordinates
- 47.52136, -122.35946
Within ~1 km
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See also: most efficient in Seattle · biggest emitters
How does Bluestone Apts compare with other multifamily housing buildings in Seattle?
The latest disclosures cover 1,971 multifamily housing buildings in Seattle, out of 3,871 buildings citywide. Bluestone Apts's ENERGY STAR score of 81 compares with an average of 83 across the 1,652 that report a score; it scores higher than 31% of them and lower than 68%. Its site EUI of 23.5 kBtu/ft² is about 33% below the average of 34.9 kBtu/ft² — it uses less energy per square foot than the typical building in that group. Its emissions intensity of 0.1 kgCO₂e/ft² is about 80% below the group average of 0.7 kgCO₂e/ft².
At 51,521 sq ft, it is about 40% below the average floor area of 86,468 sq ft for those buildings. It was built in 2017, 34 years later than the group's average year built (1983). 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 Bluestone Apts's energy performance changed over time?
BuildingCensus holds 8 Seattle disclosures for Bluestone Apts, covering report years 2018–2025. Its ENERGY STAR score went from 87 in 2018 to 81 in 2025 (-6 points); its best year on file was 2018, at 87. Site EUI moved from 21.8 kBtu/ft² (2018) to 23.5 kBtu/ft² (2025), an 8% increase. Reported emissions went from 7 tCO₂e to 7 tCO₂e over the same span (up 7%).
What does an ENERGY STAR score of 81 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 81 means the building performs better than about 81% of its national peers. BuildingCensus bands the score into report-card grades; 81 falls in band B — above median (70–84). Scores of 75 or higher meet the threshold for ENERGY STAR certification; certification itself is a separate, verified application that the disclosure does not record. In Seattle, 69% 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. Bluestone Apts's 23.5 kBtu/ft² across 51,521 sq ft works out to about 1.2 billion Btu (355 MWh-equivalent) in 2025. Its source EUI of 65.9 kBtu/ft² also counts the energy lost generating and delivering that power, which is why it is higher. The disclosure also reports 355,124 kWh of electricity for the year.
Which law requires Bluestone Apts to report its energy use?
Bluestone Apts reports under the Seattle Energy Benchmarking Ordinance (SMC 22.920), the legal basis of Seattle's Building Energy Benchmarking program, which publishes each covered building's annual benchmarking results. The record shown here is the report-year 2025 disclosure (source record seattle:50312:2025). Seattle's Building Emissions Performance Standard (adopted 2023) applies to buildings over 20,000 sq ft: benchmarking verification is due 2027–2030 and initial emissions targets 2031–2035, reaching net zero by 2041–2050, with fines for non-compliance.
More multifamily housing buildings in Seattle
- Kimberly Apts· 51,510 sq ft · score 27 (D)
- Cal-More Circle Apts· 51,490 sq ft · score 96 (A)
- Vox Apartments· 51,424 sq ft · score 100 (A)
- Genesee Apartments· 51,405 sq ft · score 76 (B)
- King County- Mary Pilgrim Housing· 51,390 sq ft · score 93 (A)
- Pinehurst Apts· 51,387 sq ft · score 93 (A)
- Multifamily Housing buildings in Seattle· 1,971 benchmarked
- All Seattle benchmarked buildings· Seattle Energy Benchmarking Ordinance (SMC 22.920)
- Most efficient large buildings in Seattle
- Least efficient large buildings in Seattle
- Biggest emitters in Seattle
Frequently asked questions
What is Bluestone Apts's energy grade?
Bluestone Apts scores 81 out of 100 on ENERGY STAR — band B, above median (70–84) — in its 2025 Seattle disclosure. Scores are national percentiles against similar buildings; 75+ qualifies for ENERGY STAR certification.
How much energy does Bluestone Apts use?
Its 2025 site energy-use intensity was 23.5 kBtu/ft² (65.9 kBtu/ft² source) across 51,521 sq ft, including 355,124 kWh of electricity.
What are Bluestone Apts's carbon emissions?
Bluestone Apts reported 7 tCO₂e of greenhouse-gas emissions (0.1 kgCO₂e/ft²) for 2025.
Where is Bluestone Apts?
Bluestone Apts is at 9051 20TH AVE SW, in Seattle, Washington 98106. Its coordinates are 47.52136, -122.35946 (latitude, longitude), as published in the Building Energy Benchmarking file.
How big is Bluestone Apts and when was it built?
Bluestone Apts has 51,521 sq ft of gross floor area, as reported in its 2025 disclosure. The disclosure lists 2017 as its year built. It is classed as multifamily housing.
Is Bluestone Apts covered by the Seattle Energy Benchmarking Ordinance (SMC 22.920)?
Yes — it appears in the 2025 Building Energy Benchmarking disclosure, which lists the buildings reporting under the Seattle Energy Benchmarking Ordinance (SMC 22.920).
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About this data
Source: Building Energy Benchmarking (Seattle Energy Benchmarking Ordinance (SMC 22.920)), as published October 2, 2026. See the methodology for how records are matched, cleaned and scored.
Cite as: BuildingCensus, “Bluestone Apts, Seattle, Washington — 2025 benchmarking disclosure”, https://buildingcensus.com/buildings/seattle/bluestone-apts-df31f1cd (data as of October 2, 2026).