At a glance
605 Union Station is a 268,130-square-foot office building at 605 5TH AVE S in Seattle, Washington, built in 2000. In its 2025 Seattle benchmarking disclosure it reported a site energy-use intensity of 28.3 kBtu/ft².
Seattle Energy Benchmarking Ordinance (SMC 22.920) · reporting year 2025
Benchmarking record
| Field | Value |
|---|---|
| ENERGY STAR score | — |
| Site EUI | 28.3 kBtu/ft² |
| Source EUI | 78.0 kBtu/ft² |
| GHG emissions | — |
| GHG intensity | — |
| Electricity | 2,171,640 kWh |
| Natural gas | 1,695 therms |
| Gross floor area | 268,130 sq ft |
| Source record | seattle:29550:2025 |
The disclosure history
Year over year
| Year | Score | Δ | Site EUI | GHG emissions |
|---|---|---|---|---|
| 2025latest | — | 28.3 kBtu/ft² | — | |
| 2024 | — | 27.8 kBtu/ft² | 50 tCO₂e | |
| 2023 | 71 | -11 | 36.6 kBtu/ft² | 61 tCO₂e |
| 2022 | 82 | -2 | 30.2 kBtu/ft² | 53 tCO₂e |
| 2021 | 84 | +2 | 29.6 kBtu/ft² | 54 tCO₂e |
| 2020 | 82 | -5 | 38.1 kBtu/ft² | 60 tCO₂e |
| 2019 | 87 | +3 | 49.6 kBtu/ft² | 77 tCO₂e |
| 2018 | 84 | +1 | 52.9 kBtu/ft² | 83 tCO₂e |
| 2017 | 83 | -5 | 52.8 kBtu/ft² | 84 tCO₂e |
| 2016 | 88 | -1 | 56.0 kBtu/ft² | 89 tCO₂e |
| 2015 | 89 | 58.1 kBtu/ft² | 92 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
- 605 5TH AVE S
- City
- Seattle
- State
- Washington
- ZIP
- 98104
- Coordinates
- 47.59705, -122.32813
Within ~1 km
Nearby benchmarked buildings
- Columbia Centerscore 90
Office · 1,952,220 sq ft
Hospital (General Medical & Surgical) · 1,926,841 sq ft
- Centurylink Field-Stadiumscore —
Stadium (Open) · 1,913,640 sq ft
- Seattle Municipal Towerscore 86
Office · 1,354,987 sq ft
- 999 Third Avescore 88
Office · 1,323,055 sq ft
- T-Mobile Park (Safeco Field)score —
Other - Entertainment/Public Assembly · 1,172,127 sq ft
See also: most efficient in Seattle · biggest emitters
How does 605 Union Station compare with other office buildings in Seattle?
The latest disclosures cover 497 office buildings in Seattle, out of 3,871 buildings citywide. Its site EUI of 28.3 kBtu/ft² is about 37% below the average of 44.8 kBtu/ft² — it uses less energy per square foot than the typical building in that group.
At 268,130 sq ft, it is about 36% 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 605 Union Station's energy performance changed over time?
BuildingCensus holds 11 Seattle disclosures for 605 Union Station, covering report years 2015–2025. Its ENERGY STAR score went from 89 in 2015 to 71 in 2023 (-18 points); its best year on file was 2015, at 89. Site EUI moved from 58.1 kBtu/ft² (2015) to 28.3 kBtu/ft² (2025), a 51% decrease. Reported emissions went from 92 tCO₂e to 50 tCO₂e over the same span (down 46%).
What does a site EUI of 28.3 kBtu/ft² mean?
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. 605 Union Station's 28.3 kBtu/ft² across 268,130 sq ft works out to about 7.6 billion Btu (2,224 MWh-equivalent) in 2025. Its source EUI of 78.0 kBtu/ft² also counts the energy lost generating and delivering that power, which is why it is higher. The disclosure also reports 2,171,640 kWh of electricity and 1,695 therms of natural gas for the year.
Which law requires 605 Union Station to report its energy use?
605 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:29550:2025). 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
- 400 Westlake Building· 268,005 sq ft · score 100 (A)
- PLAZA 600 BUILDING· 265,851 sq ft · score 81 (B)
- Amazon- Unicorn· 254,218 sq ft · score 62 (C)
- 3101 Western (Formerly Airborne Bldg)· 253,103 sq ft · score 3 (D)
- World Trade Center North· 251,044 sq ft · score 100 (A)
- Fremont Lake Union Center - Plaza Bldg· 243,334 sq ft · score 98 (A)
- 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 605 Union Station's energy grade?
605 Union Station did not report an ENERGY STAR score in its 2025 disclosure, but its site energy-use intensity was 28.3 kBtu/ft².
How much energy does 605 Union Station use?
Its 2025 site energy-use intensity was 28.3 kBtu/ft² (78.0 kBtu/ft² source) across 268,130 sq ft, including 2,171,640 kWh of electricity and 1,695 therms of natural gas.
What are 605 Union Station's carbon emissions?
No greenhouse-gas emissions figure was reported for 2025.
Where is 605 Union Station?
605 Union Station is at 605 5TH AVE S, in Seattle, Washington 98104. Its coordinates are 47.59705, -122.32813 (latitude, longitude), as published in the Building Energy Benchmarking file.
How big is 605 Union Station and when was it built?
605 Union Station has 268,130 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 605 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, “605 Union Station, Seattle, Washington — 2025 benchmarking disclosure”, https://buildingcensus.com/buildings/seattle/605-union-station-b4735a17 (data as of October 2, 2026).