Union Bay Plaza
Medical Office in Seattle, WA · 4540 UNION BAY PL NE · 98105
At a glance
Union Bay Plaza is a 22,135-square-foot medical office at 4540 UNION BAY PL NE in Seattle, Washington, built in 1945.
Seattle Energy Benchmarking Ordinance (SMC 22.920) · reporting year 2025
Benchmarking record
| Field | Value |
|---|---|
| ENERGY STAR score | — |
| Site EUI | — |
| Source EUI | — |
| GHG emissions | — |
| GHG intensity | — |
| Electricity | 244,743 kWh |
| Gross floor area | 22,135 sq ft |
| Source record | seattle:21916:2025 |
The disclosure history
Year over year
| Year | Score | Δ | Site EUI | GHG emissions |
|---|---|---|---|---|
| 2025latest | — | — | — | |
| 2024 | 61 | +9 | 65.1 kBtu/ft² | 42 tCO₂e |
| 2023 | 52 | 67.5 kBtu/ft² | 43 tCO₂e | |
| 2022 | — | — | 6 tCO₂e | |
| 2021 | — | — | — | |
| 2020 | — | 34.2 kBtu/ft² | 17 tCO₂e | |
| 2019 | — | 37.5 kBtu/ft² | 17 tCO₂e | |
| 2018 | — | 60.0 kBtu/ft² | 29 tCO₂e | |
| 2017 | — | 56.8 kBtu/ft² | 30 tCO₂e | |
| 2016 | — | 55.0 kBtu/ft² | 26 tCO₂e | |
| 2015 | — | 55.0 kBtu/ft² | 24 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.
Own or manage this building? Claim it to correct the record and get compliance alerts.
Location
- Address
- 4540 UNION BAY PL NE
- City
- Seattle
- State
- Washington
- ZIP
- 98105
- Coordinates
- 47.66246, -122.29342
Within ~1 km
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See also: most efficient in Seattle · biggest emitters
How does Union Bay Plaza compare with other medical office buildings in Seattle?
The latest disclosures cover 45 medical office buildings in Seattle, out of 3,871 buildings citywide.
At 22,135 sq ft, it is about 85% below the average floor area of 145,612 sq ft for those buildings. It was built in 1945, 34 years earlier than the group's average year built (1979). Across all 24 jurisdictions BuildingCensus covers, the 1,266 medical office buildings average an ENERGY STAR score of 64 and a site EUI of 92.2 kBtu/ft².
How has Union Bay Plaza's energy performance changed over time?
BuildingCensus holds 11 Seattle disclosures for Union Bay Plaza, covering report years 2015–2025. Its ENERGY STAR score went from 52 in 2023 to 61 in 2024 (+9 points). Site EUI moved from 55.0 kBtu/ft² (2015) to 65.1 kBtu/ft² (2024), an 18% increase. Reported emissions went from 24 tCO₂e to 42 tCO₂e over the same span (up 72%).
Which law requires Union Bay Plaza to report its energy use?
Union Bay Plaza 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:21916:2025). 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 medical office buildings in Seattle
Frequently asked questions
What is Union Bay Plaza's energy grade?
Union Bay Plaza did not report an ENERGY STAR score in its 2025 disclosure.
How much energy does Union Bay Plaza use?
No energy-use intensity was reported for 2025.
What are Union Bay Plaza's carbon emissions?
No greenhouse-gas emissions figure was reported for 2025.
Where is Union Bay Plaza?
Union Bay Plaza is at 4540 UNION BAY PL NE, in Seattle, Washington 98105. Its coordinates are 47.66246, -122.29342 (latitude, longitude), as published in the Building Energy Benchmarking file.
How big is Union Bay Plaza and when was it built?
Union Bay Plaza has 22,135 sq ft of gross floor area, as reported in its 2025 disclosure. The disclosure lists 1945 as its year built. It is classed as medical office.
Is Union Bay Plaza 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, “Union Bay Plaza, Seattle, Washington — 2025 benchmarking disclosure”, https://buildingcensus.com/buildings/seattle/union-bay-plaza-4c4ec55e (data as of October 2, 2026).