At a glance
505 Union Station is a 312,512-square-foot office building at 505 5TH AVE S in Seattle, Washington, built in 2000. In its 2025 Seattle benchmarking disclosure it reported an ENERGY STAR score of 50 out of 100 (grade D), a site energy-use intensity of 51.8 kBtu/ft² and 88 tCO₂e of greenhouse-gas emissions. That score is higher than 11% of the 378 scored office buildings in Seattle.
Seattle Energy Benchmarking Ordinance (SMC 22.920) · reporting year 2025
Benchmarking record
| Field | Value |
|---|---|
| ENERGY STAR score | 50 (band D) |
| Site EUI | 51.8 kBtu/ft² |
| Source EUI | 145.1 kBtu/ft² |
| GHG emissions | 88 tCO₂e |
| GHG intensity | 0.3 kgCO₂e/ft² |
| Electricity | 4,429,618 kWh |
| Gross floor area | 312,512 sq ft |
| Source record | seattle:658:2025 |
The disclosure history
Year over year
| Year | Score | Δ | Site EUI | GHG emissions |
|---|---|---|---|---|
| 2025latest | 50 | +11 | 51.8 kBtu/ft² | 88 tCO₂e |
| 2024 | 39 | +7 | 56.8 kBtu/ft² | 96 tCO₂e |
| 2023 | 32 | +4 | 76.0 kBtu/ft² | 129 tCO₂e |
| 2022 | 28 | -4 | 79.7 kBtu/ft² | 135 tCO₂e |
| 2021 | 32 | -31 | 75.9 kBtu/ft² | 128 tCO₂e |
| 2020 | 63 | -2 | 71.8 kBtu/ft² | 129 tCO₂e |
| 2019 | 65 | +11 | 69.4 kBtu/ft² | 132 tCO₂e |
| 2018 | 54 | 78.2 kBtu/ft² | 149 tCO₂e | |
| 2017 | — | 77.8 kBtu/ft² | 147 tCO₂e | |
| 2016 | — | 82.4 kBtu/ft² | 155 tCO₂e | |
| 2015 | — | 84.2 kBtu/ft² | 162 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
- 505 5TH AVE S
- City
- Seattle
- State
- Washington
- ZIP
- 98104
- Coordinates
- 47.59865, -122.32854
Within ~1 km
Nearby benchmarked buildings
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- Centurylink Field-Stadiumscore —
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- Seattle Municipal Towerscore 86
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- 999 Third Avescore 88
Office · 1,323,055 sq ft
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See also: most efficient in Seattle · biggest emitters
How does 505 Union Station compare with other office buildings in Seattle?
The latest disclosures cover 497 office buildings in Seattle, out of 3,871 buildings citywide. 505 Union Station's ENERGY STAR score of 50 compares with an average of 76 across the 378 that report a score; it scores higher than 11% of them and lower than 89%. Its site EUI of 51.8 kBtu/ft² is about 16% above the average of 44.8 kBtu/ft² — it uses more energy per square foot than the typical building in that group. Its emissions intensity of 0.3 kgCO₂e/ft² is about 57% below the group average of 0.7 kgCO₂e/ft².
At 312,512 sq ft, it is about 59% above the average floor area of 196,452 sq ft for those buildings. It was built in 2000, 35 years later than the group's average year built (1965). 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 505 Union Station's energy performance changed over time?
BuildingCensus holds 11 Seattle disclosures for 505 Union Station, covering report years 2015–2025. Its ENERGY STAR score went from 54 in 2018 to 50 in 2025 (-4 points); its best year on file was 2019, at 65. Site EUI moved from 84.2 kBtu/ft² (2015) to 51.8 kBtu/ft² (2025), a 38% decrease. Reported emissions went from 162 tCO₂e to 88 tCO₂e over the same span (down 46%).
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 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. 505 Union Station's 51.8 kBtu/ft² across 312,512 sq ft works out to about 16.2 billion Btu (4,744 MWh-equivalent) in 2025. Its source EUI of 145.1 kBtu/ft² also counts the energy lost generating and delivering that power, which is why it is higher. The disclosure also reports 4,429,618 kWh of electricity for the year.
Which law requires 505 Union Station to report its energy use?
505 Union Station 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:658:2025). 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 office buildings in Seattle
- Waterfront Place Building Mixed Use Condominium· 307,557 sq ft · score 86 (A)
- Tilt 49 (Office Portion)· 305,542 sq ft · score 96 (A)
- Smith Tower· 304,346 sq ft · score 73 (B)
- Westlake Terry West Bldg· 303,103 sq ft · score 94 (A)
- 1015 Third Avenue Bldg - Expeditors International· 293,576 sq ft · score 66 (C)
- 635 ELLIOTT - SOUTH BUILDING· 291,176 sq ft · score 65 (C)
- Office buildings in Seattle· 497 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 505 Union Station's energy grade?
505 Union Station scores 50 out of 100 on ENERGY STAR — band D, lowest band (1–54) — in its 2025 Seattle disclosure. Scores are national percentiles against similar buildings; 75+ qualifies for ENERGY STAR certification.
How much energy does 505 Union Station use?
Its 2025 site energy-use intensity was 51.8 kBtu/ft² (145.1 kBtu/ft² source) across 312,512 sq ft, including 4,429,618 kWh of electricity.
What are 505 Union Station's carbon emissions?
505 Union Station reported 88 tCO₂e of greenhouse-gas emissions (0.3 kgCO₂e/ft²) for 2025.
Where is 505 Union Station?
505 Union Station is at 505 5TH AVE S, in Seattle, Washington 98104. Its coordinates are 47.59865, -122.32854 (latitude, longitude), as published in the Building Energy Benchmarking file.
How big is 505 Union Station and when was it built?
505 Union Station has 312,512 sq ft of gross floor area, as reported in its 2025 disclosure. The disclosure lists 2000 as its year built. It is classed as office.
Is 505 Union Station 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, “505 Union Station, Seattle, Washington — 2025 benchmarking disclosure”, https://buildingcensus.com/buildings/seattle/505-union-station-a65ee75c (data as of October 2, 2026).