At a glance
Iridio - (Old Western Cartage) is a 50,008-square-foot office building at 5050 1ST AVE S in Seattle, Washington, built in 1938. In its 2025 Seattle benchmarking disclosure it reported a site energy-use intensity of 20.1 kBtu/ft² and 24 tCO₂e of greenhouse-gas emissions.
Seattle Energy Benchmarking Ordinance (SMC 22.920) · reporting year 2025
Benchmarking record
| Field | Value |
|---|---|
| ENERGY STAR score | — |
| Site EUI | 20.1 kBtu/ft² |
| Source EUI | 42.0 kBtu/ft² |
| GHG emissions | 24 tCO₂e |
| GHG intensity | 0.5 kgCO₂e/ft² |
| Electricity | 174,961 kWh |
| Natural gas | 4,096 therms |
| Gross floor area | 50,008 sq ft |
| Source record | seattle:596:2025 |
The disclosure history
Year over year
| Year | Score | Δ | Site EUI | GHG emissions |
|---|---|---|---|---|
| 2025latest | — | 20.1 kBtu/ft² | 24 tCO₂e | |
| 2024 | 96 | +5 | 27.9 kBtu/ft² | 39 tCO₂e |
| 2023 | 91 | +9 | 33.3 kBtu/ft² | 42 tCO₂e |
| 2022 | 82 | -6 | 48.5 kBtu/ft² | 75 tCO₂e |
| 2021 | 88 | -1 | 35.0 kBtu/ft² | 37 tCO₂e |
| 2020 | 89 | +8 | 34.0 kBtu/ft² | 38 tCO₂e |
| 2019 | 81 | -5 | 41.1 kBtu/ft² | 49 tCO₂e |
| 2018 | 86 | +36 | 42.0 kBtu/ft² | 61 tCO₂e |
| 2017 | 50 | -12 | 65.0 kBtu/ft² | 74 tCO₂e |
| 2016 | 62 | +5 | 64.0 kBtu/ft² | 63 tCO₂e |
| 2015 | 57 | 67.5 kBtu/ft² | 63 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
- 5050 1ST AVE S
- City
- Seattle
- State
- Washington
- ZIP
- 98134
- Coordinates
- 47.55623, -122.33316
Within ~1 km
Nearby benchmarked buildings
- Georgetown Squaredscore 74
Office · 390,295 sq ft
- K2 And Iron Mountain (Seattle 4)score 98
Non-Refrigerated Warehouse · 323,916 sq ft
- Terreno 1st Ave Southscore 75
Non-Refrigerated Warehouse · 234,144 sq ft
- Seattle Design Centerscore —
Enclosed Mall · 156,188 sq ft
- Ups Warehousescore —
Distribution Center · 141,686 sq ft
Parking · 127,065 sq ft
See also: most efficient in Seattle · biggest emitters
How does Iridio - (Old Western Cartage) compare with other office buildings in Seattle?
The latest disclosures cover 497 office buildings in Seattle, out of 3,871 buildings citywide. Its site EUI of 20.1 kBtu/ft² is about 55% below the average of 44.8 kBtu/ft² — it uses less energy per square foot than the typical building in that group. Its emissions intensity of 0.5 kgCO₂e/ft² is about 30% below the group average of 0.7 kgCO₂e/ft².
At 50,008 sq ft, it is about 75% below the average floor area of 196,452 sq ft for those buildings. It was built in 1938, 27 years earlier than the group's average year built (1965). Across all 24 jurisdictions BuildingCensus covers, the 15,264 office buildings average an ENERGY STAR score of 73 and a site EUI of 59.3 kBtu/ft².
How has Iridio - (Old Western Cartage)'s energy performance changed over time?
BuildingCensus holds 11 Seattle disclosures for Iridio - (Old Western Cartage), covering report years 2015–2025. Its ENERGY STAR score went from 57 in 2015 to 96 in 2024 (+39 points). Site EUI moved from 67.5 kBtu/ft² (2015) to 20.1 kBtu/ft² (2025), a 70% decrease. Reported emissions went from 63 tCO₂e to 24 tCO₂e over the same span (down 61%).
What does a site EUI of 20.1 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. Iridio - (Old Western Cartage)'s 20.1 kBtu/ft² across 50,008 sq ft works out to about 1 billion Btu (295 MWh-equivalent) in 2025. Its source EUI of 42.0 kBtu/ft² also counts the energy lost generating and delivering that power, which is why it is higher. The disclosure also reports 174,961 kWh of electricity and 4,096 therms of natural gas for the year.
Which law requires Iridio - (Old Western Cartage) to report its energy use?
Iridio - (Old Western Cartage) 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:596:2025). 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 office buildings in Seattle
- Northlake Building· 49,782 sq ft · score 44 (D)
- 1943 First Ave Building· 49,052 sq ft · score 98 (A)
- Ship Canal Office Center· 48,924 sq ft · score 39 (D)
- Doyle Building· 47,686 sq ft · score 90 (A)
- Western Triangle Building Condominium· 47,415 sq ft · EUI 46.7 kBtu/ft²
- Wa State Dept Of Corrections· 47,368 sq ft · score 86 (A)
- Office buildings in Seattle· 497 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 Iridio - (Old Western Cartage)'s energy grade?
Iridio - (Old Western Cartage) did not report an ENERGY STAR score in its 2025 disclosure, but its site energy-use intensity was 20.1 kBtu/ft².
How much energy does Iridio - (Old Western Cartage) use?
Its 2025 site energy-use intensity was 20.1 kBtu/ft² (42.0 kBtu/ft² source) across 50,008 sq ft, including 174,961 kWh of electricity and 4,096 therms of natural gas.
What are Iridio - (Old Western Cartage)'s carbon emissions?
Iridio - (Old Western Cartage) reported 24 tCO₂e of greenhouse-gas emissions (0.5 kgCO₂e/ft²) for 2025.
Where is Iridio - (Old Western Cartage)?
Iridio - (Old Western Cartage) is at 5050 1ST AVE S, in Seattle, Washington 98134. Its coordinates are 47.55623, -122.33316 (latitude, longitude), as published in the Building Energy Benchmarking file.
How big is Iridio - (Old Western Cartage) and when was it built?
Iridio - (Old Western Cartage) has 50,008 sq ft of gross floor area, as reported in its 2025 disclosure. The disclosure lists 1938 as its year built. It is classed as office.
Is Iridio - (Old Western Cartage) 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, “Iridio - (Old Western Cartage), Seattle, Washington — 2025 benchmarking disclosure”, https://buildingcensus.com/buildings/seattle/iridio-old-western-cartage-ad1f7c8d (data as of October 2, 2026).