Upstairs Downstairs Apartments
Multifamily Housing in Seattle, WA · 4528 18TH AVE NE · 98105
At a glance
Upstairs Downstairs Apartments is a 33,448-square-foot multifamily housing building at 4528 18TH AVE NE in Seattle, Washington, built in 1976. In its 2025 Seattle benchmarking disclosure it reported a site energy-use intensity of 12.4 kBtu/ft² and 2 tCO₂e of greenhouse-gas emissions.
Seattle Energy Benchmarking Ordinance (SMC 22.920) · reporting year 2025
Benchmarking record
| Field | Value |
|---|---|
| ENERGY STAR score | — |
| Site EUI | 12.4 kBtu/ft² |
| Source EUI | 34.6 kBtu/ft² |
| GHG emissions | 2 tCO₂e |
| GHG intensity | 0.1 kgCO₂e/ft² |
| Electricity | 126,738 kWh |
| Gross floor area | 33,448 sq ft |
| Source record | seattle:26922:2025 |
The disclosure history
Year over year
| Year | Score | Δ | Site EUI | GHG emissions |
|---|---|---|---|---|
| 2025latest | — | 12.4 kBtu/ft² | 2 tCO₂e | |
| 2024 | — | 15.3 kBtu/ft² | 3 tCO₂e | |
| 2023 | — | 17.2 kBtu/ft² | 4 tCO₂e | |
| 2022 | — | 13.7 kBtu/ft² | 3 tCO₂e | |
| 2021 | — | 15.3 kBtu/ft² | 3 tCO₂e | |
| 2020 | — | 17.5 kBtu/ft² | 4 tCO₂e | |
| 2019 | — | 20.3 kBtu/ft² | 4 tCO₂e | |
| 2018 | — | 22.7 kBtu/ft² | 5 tCO₂e | |
| 2017 | — | 19.7 kBtu/ft² | 4 tCO₂e | |
| 2016 | 78 | +1 | 29.9 kBtu/ft² | 6 tCO₂e |
| 2015 | 77 | 29.0 kBtu/ft² | 6 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
- 4528 18TH AVE NE
- City
- Seattle
- State
- Washington
- ZIP
- 98105
- Coordinates
- 47.66238, -122.30801
Within ~1 km
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See also: most efficient in Seattle · biggest emitters
How does Upstairs Downstairs Apartments 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. Its site EUI of 12.4 kBtu/ft² is about 64% 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 90% below the group average of 0.7 kgCO₂e/ft².
At 33,448 sq ft, it is about 61% below the average floor area of 86,468 sq ft for those buildings. It was built in 1976, 7 years earlier 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 Upstairs Downstairs Apartments's energy performance changed over time?
BuildingCensus holds 11 Seattle disclosures for Upstairs Downstairs Apartments, covering report years 2015–2025. Its ENERGY STAR score went from 77 in 2015 to 78 in 2016 (+1 points). Site EUI moved from 29.0 kBtu/ft² (2015) to 12.4 kBtu/ft² (2025), a 57% decrease. Reported emissions went from 6 tCO₂e to 2 tCO₂e over the same span (down 57%).
What does a site EUI of 12.4 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. Upstairs Downstairs Apartments's 12.4 kBtu/ft² across 33,448 sq ft works out to about 0.4 billion Btu (122 MWh-equivalent) in 2025. Its source EUI of 34.6 kBtu/ft² also counts the energy lost generating and delivering that power, which is why it is higher. The disclosure also reports 126,738 kWh of electricity for the year.
Which law requires Upstairs Downstairs Apartments to report its energy use?
Upstairs Downstairs Apartments 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:26922:2025). 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
- Lexington Concord Apts· 33,440 sq ft · score 48 (D)
- Renaissance At 1st & Lee· 33,440 sq ft · EUI 48.9 kBtu/ft²
- Gables Coop Apts· 33,430 sq ft · score 65 (C)
- Bremer Apartments· 33,400 sq ft · score 91 (A)
- Harbour House At Leschi Condominium· 33,331 sq ft · EUI 29.5 kBtu/ft²
- Emerald Arms· 33,279 sq ft · score 83 (B)
- 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 Upstairs Downstairs Apartments's energy grade?
Upstairs Downstairs Apartments did not report an ENERGY STAR score in its 2025 disclosure, but its site energy-use intensity was 12.4 kBtu/ft².
How much energy does Upstairs Downstairs Apartments use?
Its 2025 site energy-use intensity was 12.4 kBtu/ft² (34.6 kBtu/ft² source) across 33,448 sq ft, including 126,738 kWh of electricity.
What are Upstairs Downstairs Apartments's carbon emissions?
Upstairs Downstairs Apartments reported 2 tCO₂e of greenhouse-gas emissions (0.1 kgCO₂e/ft²) for 2025.
Where is Upstairs Downstairs Apartments?
Upstairs Downstairs Apartments is at 4528 18TH AVE NE, in Seattle, Washington 98105. Its coordinates are 47.66238, -122.30801 (latitude, longitude), as published in the Building Energy Benchmarking file.
How big is Upstairs Downstairs Apartments and when was it built?
Upstairs Downstairs Apartments has 33,448 sq ft of gross floor area, as reported in its 2025 disclosure. The disclosure lists 1976 as its year built. It is classed as multifamily housing.
Is Upstairs Downstairs Apartments 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, “Upstairs Downstairs Apartments, Seattle, Washington — 2025 benchmarking disclosure”, https://buildingcensus.com/buildings/seattle/upstairs-downstairs-apartments-637f8382 (data as of October 2, 2026).