Helix Apartments
Multifamily Housing in Seattle, WA · 4751 12TH AVE NE · 98105
At a glance
Helix Apartments is a 65,826-square-foot multifamily housing building at 4751 12TH AVE NE in Seattle, Washington, built in 2006. In its 2025 Seattle benchmarking disclosure it reported a site energy-use intensity of 32.1 kBtu/ft² and 12 tCO₂e of greenhouse-gas emissions.
Seattle Energy Benchmarking Ordinance (SMC 22.920) · reporting year 2025
Benchmarking record
| Field | Value |
|---|---|
| ENERGY STAR score | — |
| Site EUI | 32.1 kBtu/ft² |
| Source EUI | 89.8 kBtu/ft² |
| GHG emissions | 12 tCO₂e |
| GHG intensity | 0.2 kgCO₂e/ft² |
| Electricity | 618,933 kWh |
| Gross floor area | 65,826 sq ft |
| Source record | seattle:27884:2025 |
The disclosure history
Year over year
| Year | Score | Δ | Site EUI | GHG emissions |
|---|---|---|---|---|
| 2025latest | — | 32.1 kBtu/ft² | 12 tCO₂e | |
| 2024 | — | 33.9 kBtu/ft² | 13 tCO₂e | |
| 2023 | — | 31.8 kBtu/ft² | 12 tCO₂e | |
| 2022 | — | 33.4 kBtu/ft² | 13 tCO₂e | |
| 2021 | — | 30.4 kBtu/ft² | 12 tCO₂e | |
| 2020 | — | 30.5 kBtu/ft² | 12 tCO₂e | |
| 2019 | — | 33.8 kBtu/ft² | 13 tCO₂e | |
| 2018 | — | 35.1 kBtu/ft² | 13 tCO₂e | |
| 2017 | — | 33.1 kBtu/ft² | 13 tCO₂e | |
| 2016 | — | 35.5 kBtu/ft² | 14 tCO₂e | |
| 2015 | — | 35.5 kBtu/ft² | 14 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
- 4751 12TH AVE NE
- City
- Seattle
- State
- Washington
- ZIP
- 98105
- Coordinates
- 47.66460, -122.31558
Within ~1 km
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See also: most efficient in Seattle · biggest emitters
How does Helix 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 32.1 kBtu/ft² is roughly in line with 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 74% below the group average of 0.7 kgCO₂e/ft².
At 65,826 sq ft, it is about 24% below the average floor area of 86,468 sq ft for those buildings. It was built in 2006, 23 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 Helix Apartments's energy performance changed over time?
BuildingCensus holds 11 Seattle disclosures for Helix Apartments, covering report years 2015–2025. Site EUI moved from 35.5 kBtu/ft² (2015) to 32.1 kBtu/ft² (2025), a 10% decrease. Reported emissions went from 14 tCO₂e to 12 tCO₂e over the same span (down 11%).
What does a site EUI of 32.1 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. Helix Apartments's 32.1 kBtu/ft² across 65,826 sq ft works out to about 2.1 billion Btu (619 MWh-equivalent) in 2025. Its source EUI of 89.8 kBtu/ft² also counts the energy lost generating and delivering that power, which is why it is higher. The disclosure also reports 618,933 kWh of electricity for the year.
Which law requires Helix Apartments to report its energy use?
Helix 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:27884:2025). 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
- First And Republican Apts· 65,712 sq ft · score 99 (A)
- Maple Leaf Plaza Apts + Retail· 65,694 sq ft · score 91 (A)
- Crosspointe Vista· 65,689 sq ft · score 92 (A)
- Epic Condominium· 65,604 sq ft · score 98 (A)
- Harbor House On Queen Anne Condominium· 65,538 sq ft · score 75 (B)
- Lowman Building· 65,535 sq ft · EUI 20.3 kBtu/ft²
- 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 Helix Apartments's energy grade?
Helix Apartments did not report an ENERGY STAR score in its 2025 disclosure, but its site energy-use intensity was 32.1 kBtu/ft².
How much energy does Helix Apartments use?
Its 2025 site energy-use intensity was 32.1 kBtu/ft² (89.8 kBtu/ft² source) across 65,826 sq ft, including 618,933 kWh of electricity.
What are Helix Apartments's carbon emissions?
Helix Apartments reported 12 tCO₂e of greenhouse-gas emissions (0.2 kgCO₂e/ft²) for 2025.
Where is Helix Apartments?
Helix Apartments is at 4751 12TH AVE NE, in Seattle, Washington 98105. Its coordinates are 47.66460, -122.31558 (latitude, longitude), as published in the Building Energy Benchmarking file.
How big is Helix Apartments and when was it built?
Helix Apartments has 65,826 sq ft of gross floor area, as reported in its 2025 disclosure. The disclosure lists 2006 as its year built. It is classed as multifamily housing.
Is Helix 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, “Helix Apartments, Seattle, Washington — 2025 benchmarking disclosure”, https://buildingcensus.com/buildings/seattle/helix-apartments-6e9a9b25 (data as of October 2, 2026).