Westerly Condominium
Multifamily Housing in Seattle, WA · 4540 45TH AVE SW · 98116
At a glance
Westerly Condominium is a 20,407-square-foot multifamily housing building at 4540 45TH AVE SW in Seattle, Washington, built in 1989. In its 2025 Seattle benchmarking disclosure it reported an ENERGY STAR score of 82 out of 100 (grade B), a site energy-use intensity of 29.5 kBtu/ft² and 3 tCO₂e of greenhouse-gas emissions. That score is higher than 32% 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 | 82 (band B) |
| Site EUI | 29.5 kBtu/ft² |
| Source EUI | 82.7 kBtu/ft² |
| GHG emissions | 3 tCO₂e |
| GHG intensity | 0.2 kgCO₂e/ft² |
| Electricity | 147,169 kWh |
| Gross floor area | 20,407 sq ft |
| Source record | seattle:25883:2025 |
The disclosure history
Year over year
| Year | Score | Δ | Site EUI | GHG emissions |
|---|---|---|---|---|
| 2025latest | 82 | -1 | 29.5 kBtu/ft² | 3 tCO₂e |
| 2024 | 83 | -3 | 29.0 kBtu/ft² | 3 tCO₂e |
| 2023 | 86 | +3 | 28.9 kBtu/ft² | 3 tCO₂e |
| 2022 | 83 | +2 | 30.5 kBtu/ft² | 3 tCO₂e |
| 2021 | 81 | +5 | 30.7 kBtu/ft² | 3 tCO₂e |
| 2020 | 76 | -3 | 31.0 kBtu/ft² | 3 tCO₂e |
| 2019 | 79 | -5 | 30.3 kBtu/ft² | 3 tCO₂e |
| 2018 | 84 | -6 | 28.6 kBtu/ft² | 3 tCO₂e |
| 2017 | 90 | +17 | 26.8 kBtu/ft² | 3 tCO₂e |
| 2016 | 73 | +53 | 29.9 kBtu/ft² | 3 tCO₂e |
| 2015 | 20 | 28.9 kBtu/ft² | 3 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 45TH AVE SW
- City
- Seattle
- State
- Washington
- ZIP
- 98116
- Coordinates
- 47.56178, -122.38910
Within ~1 km
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See also: most efficient in Seattle · biggest emitters
How does Westerly Condominium 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. Westerly Condominium's ENERGY STAR score of 82 compares with an average of 83 across the 1,652 that report a score; it scores higher than 32% of them and lower than 66%. Its site EUI of 29.5 kBtu/ft² is about 15% 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 0.2 kgCO₂e/ft² is about 76% below the group average of 0.7 kgCO₂e/ft².
At 20,407 sq ft, it is about 76% below the average floor area of 86,468 sq ft for those buildings. It was built in 1989, 6 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 Westerly Condominium's energy performance changed over time?
BuildingCensus holds 11 Seattle disclosures for Westerly Condominium, covering report years 2015–2025. Its ENERGY STAR score went from 20 in 2015 to 82 in 2025 (+62 points); its best year on file was 2017, at 90. Site EUI moved from 28.9 kBtu/ft² (2015) to 29.5 kBtu/ft² (2025), an 2% increase. Reported emissions went from 3 tCO₂e to 3 tCO₂e over the same span (up 3%).
What does an ENERGY STAR score of 82 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 82 means the building performs better than about 82% of its national peers. BuildingCensus bands the score into report-card grades; 82 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. Westerly Condominium's 29.5 kBtu/ft² across 20,407 sq ft works out to about 0.6 billion Btu (176 MWh-equivalent) in 2025. Its source EUI of 82.7 kBtu/ft² also counts the energy lost generating and delivering that power, which is why it is higher. The disclosure also reports 147,169 kWh of electricity for the year.
Which law requires Westerly Condominium to report its energy use?
Westerly Condominium 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:25883:2025). 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
- 515 First Avenue West Condominium· 20,406 sq ft · EUI 29.3 kBtu/ft²
- Gale Place Apts· 20,400 sq ft · score 80 (B)
- Ravenna House Condominium· 20,390 sq ft · EUI 22.2 kBtu/ft²
- Lynnyale Apts· 20,384 sq ft · score 100 (A)
- Villa Anita Apts· 20,383 sq ft · EUI 22.3 kBtu/ft²
- Mezzo Condominium· 20,380 sq ft · score 85 (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 Westerly Condominium's energy grade?
Westerly Condominium scores 82 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 Westerly Condominium use?
Its 2025 site energy-use intensity was 29.5 kBtu/ft² (82.7 kBtu/ft² source) across 20,407 sq ft, including 147,169 kWh of electricity.
What are Westerly Condominium's carbon emissions?
Westerly Condominium reported 3 tCO₂e of greenhouse-gas emissions (0.2 kgCO₂e/ft²) for 2025.
Where is Westerly Condominium?
Westerly Condominium is at 4540 45TH AVE SW, in Seattle, Washington 98116. Its coordinates are 47.56178, -122.38910 (latitude, longitude), as published in the Building Energy Benchmarking file.
How big is Westerly Condominium and when was it built?
Westerly Condominium has 20,407 sq ft of gross floor area, as reported in its 2025 disclosure. The disclosure lists 1989 as its year built. It is classed as multifamily housing.
Is Westerly Condominium 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, “Westerly Condominium, Seattle, Washington — 2025 benchmarking disclosure”, https://buildingcensus.com/buildings/seattle/westerly-condominium-a4fd9a52 (data as of October 2, 2026).