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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.

ENERGY STAR score
99
band A · 2025
Site EUI
28.9
kBtu/ft²
GHG emissions
245
tCO₂e
GHG intensity
0.6
kgCO₂e/ft²
Floor area
651,374
sq ft
Year built
2018
vintage
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85–10070–8455–691–54
This entry + 6 nearby

Seattle Energy Benchmarking Ordinance (SMC 22.920) · reporting year 2025

Benchmarking record

FieldValue
ENERGY STAR score99 (band A)
Site EUI28.9 kBtu/ft²
Source EUI66.5 kBtu/ft²
GHG emissions245 tCO₂e
GHG intensity0.6 kgCO₂e/ft²
Electricity2,688,006 kWh
Natural gas36,914 therms
Gross floor area651,374 sq ft
Source recordseattle:50667:2025

The disclosure history

Year over year

YearScoreΔSite EUIGHG emissions
2025latest99+1028.9 kBtu/ft²245 tCO₂e
202489-1043.4 kBtu/ft²567 tCO₂e
202399-129.9 kBtu/ft²315 tCO₂e
2022100±030.7 kBtu/ft²329 tCO₂e
2021100+528.3 kBtu/ft²189 tCO₂e
20204851.2 kBtu/ft²229 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.

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Ownership

No owning organisation shown. Names of private individuals in the disclosure are not published here.

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Location

Address
1146 HARRISON ST
State
Washington
ZIP
98109
Coordinates
47.62262, -122.33483

Within ~1 km

Nearby benchmarked buildings

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

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).

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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, “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).