Ascent Slu And Marlowe
Multifamily Housing in Seattle, WA · 1146 HARRISON ST · 98109
At a glance
Ascent Slu And Marlowe is a 651,374-square-foot multifamily housing building at 1146 HARRISON ST in Seattle, Washington, built in 2018. In its 2025 Seattle benchmarking disclosure it reported an ENERGY STAR score of 99 out of 100 (grade A), a site energy-use intensity of 28.9 kBtu/ft² and 245 tCO₂e of greenhouse-gas emissions. That score is higher than 80% 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 | 99 (band A) |
| Site EUI | 28.9 kBtu/ft² |
| Source EUI | 66.5 kBtu/ft² |
| GHG emissions | 245 tCO₂e |
| GHG intensity | 0.6 kgCO₂e/ft² |
| Electricity | 2,688,006 kWh |
| Natural gas | 36,914 therms |
| Gross floor area | 651,374 sq ft |
| Source record | seattle:50667:2025 |
The disclosure history
Year over year
| Year | Score | Δ | Site EUI | GHG emissions |
|---|---|---|---|---|
| 2025latest | 99 | +10 | 28.9 kBtu/ft² | 245 tCO₂e |
| 2024 | 89 | -10 | 43.4 kBtu/ft² | 567 tCO₂e |
| 2023 | 99 | -1 | 29.9 kBtu/ft² | 315 tCO₂e |
| 2022 | 100 | ±0 | 30.7 kBtu/ft² | 329 tCO₂e |
| 2021 | 100 | +52 | 8.3 kBtu/ft² | 189 tCO₂e |
| 2020 | 48 | 51.2 kBtu/ft² | 229 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
- 1146 HARRISON ST
- City
- Seattle
- State
- Washington
- ZIP
- 98109
- Coordinates
- 47.62262, -122.33483
Within ~1 km
Nearby benchmarked buildings
Office · 1,599,394 sq ft
- Day 1 Tower And Spheres (Amazon)score 93
Office · 1,599,230 sq ft
- Onni South Lake Unionscore 77
Multifamily Housing · 1,546,084 sq ft
- Amazon Doppler Buildingscore 90
Office · 1,496,961 sq ft
- Amazon Nitroscore 94
Office · 1,323,773 sq ft
- Troy Block (Amazon)score 88
Office · 1,261,155 sq ft
See also: most efficient in Seattle · biggest emitters
How does Ascent Slu And Marlowe 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. Ascent Slu And Marlowe's ENERGY STAR score of 99 compares with an average of 83 across the 1,652 that report a score; it scores higher than 80% of them and lower than 12%. Its site EUI of 28.9 kBtu/ft² is about 17% 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 0.6 kgCO₂e/ft² is about 21% below the group average of 0.7 kgCO₂e/ft².
At 651,374 sq ft, it is about 653% above the average floor area of 86,468 sq ft for those buildings. It was built in 2018, 35 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 Ascent Slu And Marlowe's energy performance changed over time?
BuildingCensus holds 6 Seattle disclosures for Ascent Slu And Marlowe, covering report years 2020–2025. Its ENERGY STAR score went from 48 in 2020 to 99 in 2025 (+51 points); its best year on file was 2021, at 100. Site EUI moved from 51.2 kBtu/ft² (2020) to 28.9 kBtu/ft² (2025), a 44% decrease. Reported emissions went from 229 tCO₂e to 245 tCO₂e over the same span (up 7%).
What does an ENERGY STAR score of 99 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 99 means the building performs better than about 99% of its national peers. BuildingCensus bands the score into report-card grades; 99 falls in band A — high performer (85–100). 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. Ascent Slu And Marlowe's 28.9 kBtu/ft² across 651,374 sq ft works out to about 18.8 billion Btu (5,517 MWh-equivalent) in 2025. Its source EUI of 66.5 kBtu/ft² also counts the energy lost generating and delivering that power, which is why it is higher. The disclosure also reports 2,688,006 kWh of electricity and 36,914 therms of natural gas for the year.
Which law requires Ascent Slu And Marlowe to report its energy use?
Ascent Slu And Marlowe 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:50667:2025). 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
- Mckenzie· 632,252 sq ft · score 81 (B)
- Skyline At First Hill· 629,615 sq ft · score 65 (C)
- Stadium Place (The Wave & The Nolo)· 619,416 sq ft · EUI 40.1 kBtu/ft²
- Stratus Apartments- Mixed Use· 614,765 sq ft · score 69 (C)
- The Standard At Seattle· 612,844 sq ft · score 100 (A)
- The Danforth· 592,484 sq ft · score 100 (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 Ascent Slu And Marlowe's energy grade?
Ascent Slu And Marlowe scores 99 out of 100 on ENERGY STAR — band A, high performer (85–100) — in its 2025 Seattle disclosure. Scores are national percentiles against similar buildings; 75+ qualifies for ENERGY STAR certification.
How much energy does Ascent Slu And Marlowe use?
Its 2025 site energy-use intensity was 28.9 kBtu/ft² (66.5 kBtu/ft² source) across 651,374 sq ft, including 2,688,006 kWh of electricity and 36,914 therms of natural gas.
What are Ascent Slu And Marlowe's carbon emissions?
Ascent Slu And Marlowe reported 245 tCO₂e of greenhouse-gas emissions (0.6 kgCO₂e/ft²) for 2025.
Where is Ascent Slu And Marlowe?
Ascent Slu And Marlowe is at 1146 HARRISON ST, in Seattle, Washington 98109. Its coordinates are 47.62262, -122.33483 (latitude, longitude), as published in the Building Energy Benchmarking file.
How big is Ascent Slu And Marlowe and when was it built?
Ascent Slu And Marlowe has 651,374 sq ft of gross floor area, as reported in its 2025 disclosure. The disclosure lists 2018 as its year built. It is classed as multifamily housing.
Is Ascent Slu And Marlowe 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).
Working with Seattle building benchmarking records? Pro adds alerts, change history and CSV export ($49/mo); Enterprise adds full national files, the API and an MCP server for AI tools.
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, “Ascent Slu And Marlowe, Seattle, Washington — 2025 benchmarking disclosure”, https://buildingcensus.com/buildings/seattle/ascent-slu-and-marlowe-67662daa (data as of October 2, 2026).