At a glance
One South Dearborn is a 942,732-square-foot office building at 1 South Dearborn in Chicago, Illinois, built in 2005. In its 2023 Chicago benchmarking disclosure it reported an ENERGY STAR score of 81 out of 100 (grade B), a site energy-use intensity of 41.9 kBtu/ft² and 5,533 tCO₂e of greenhouse-gas emissions. That score is higher than 70% of the 320 scored office buildings in Chicago.
Building Energy Use Benchmarking Ordinance · reporting year 2023
Benchmarking record
| Field | Value |
|---|---|
| ENERGY STAR score | 81 (band B) |
| Site EUI | 41.9 kBtu/ft² |
| Source EUI | 117.4 kBtu/ft² |
| GHG emissions | 5,533 tCO₂e |
| GHG intensity | 5.9 kgCO₂e/ft² |
| Electricity | 11,588,682 kWh |
| Water use | 6,059 kgal |
| Gross floor area | 942,732 sq ft |
| Source record | chicago:101739:2023 |
The disclosure history
Year over year
| Year | Score | Δ | Site EUI | GHG emissions |
|---|---|---|---|---|
| 2023latest | 81 | +1 | 41.9 kBtu/ft² | 5,533 tCO₂e |
| 2022 | 80 | -4 | 43.6 kBtu/ft² | 5,417 tCO₂e |
| 2021 | 84 | ±0 | 40.5 kBtu/ft² | 5,459 tCO₂e |
| 2020 | 84 | 41.1 kBtu/ft² | 6,042 tCO₂e | |
| 2019 | — | — | — | |
| 2018 | 69 | -17 | 52.7 kBtu/ft² | 8,270 tCO₂e |
| 2017 | 86 | +2 | 55.8 kBtu/ft² | 9,729 tCO₂e |
| 2016 | 84 | ±0 | 58.4 kBtu/ft² | 10,143 tCO₂e |
| 2015 | 84 | +1 | 58.1 kBtu/ft² | 10,996 tCO₂e |
| 2014 | 83 | 61.0 kBtu/ft² | 11,450 tCO₂e |
Compliance context
Building Energy Use Benchmarking Ordinance
Covered buildings that fail to benchmark and report face fines of up to $100 plus $25 per day of violation under the ordinance.
Ownership
No owning organisation shown. Names of private individuals in the disclosure are not published here.
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Location
- Address
- 1 South Dearborn
- City
- Chicago
- State
- Illinois
- ZIP
- 60603
- Coordinates
- 41.88003, -87.65938
Within ~1 km
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- Misericordia Homescore —
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- The Drake, IL-SVscore 38
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See also: most efficient in Chicago · biggest emitters
How does One South Dearborn compare with other office buildings in Chicago?
The latest disclosures cover 387 office buildings in Chicago, out of 3,852 buildings citywide. One South Dearborn's ENERGY STAR score of 81 compares with an average of 69 across the 320 that report a score; it scores higher than 70% of them and lower than 27%. Its site EUI of 41.9 kBtu/ft² is about 40% below the average of 70.4 kBtu/ft² — it uses less energy per square foot than the typical building in that group. Its emissions intensity of 5.9 kgCO₂e/ft² is about 21% below the group average of 7.5 kgCO₂e/ft².
At 942,732 sq ft, it is about twice the average floor area of 488,124 sq ft for those buildings. It was built in 2005, 49 years later than the group's average year built (1957). 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 One South Dearborn's energy performance changed over time?
BuildingCensus holds 10 Chicago disclosures for One South Dearborn, covering report years 2014–2023. Its ENERGY STAR score went from 83 in 2014 to 81 in 2023 (-2 points); its best year on file was 2017, at 86. Site EUI moved from 61.0 kBtu/ft² (2014) to 41.9 kBtu/ft² (2023), a 31% decrease. Reported emissions went from 11,450 tCO₂e to 5,533 tCO₂e over the same span (down 52%).
What does an ENERGY STAR score of 81 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 81 means the building performs better than about 81% of its national peers. BuildingCensus bands the score into report-card grades; 81 falls in band B — above median (70–84). 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 Chicago, 35% 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. One South Dearborn's 41.9 kBtu/ft² across 942,732 sq ft works out to about 39.5 billion Btu (11,576 MWh-equivalent) in 2023. Its source EUI of 117.4 kBtu/ft² also counts the energy lost generating and delivering that power, which is why it is higher. The disclosure also reports 11,588,682 kWh of electricity and 6,059 thousand gallons of water for the year.
Which law requires One South Dearborn to report its energy use?
One South Dearborn reports under the Building Energy Use Benchmarking Ordinance, the legal basis of the Chicago Energy Benchmarking program, which publishes each covered building's annual benchmarking results. The record shown here is the report-year 2023 disclosure (source record chicago:101739:2023). Covered buildings that fail to benchmark and report face fines of up to $100 plus $25 per day of violation under the ordinance.
More office buildings in Chicago
- NBC Tower· 939,350 sq ft · score 58 (C)
- 55 West Monroe· 895,765 sq ft · score 77 (B)
- 190 South LaSalle· 883,718 sq ft · score 76 (B)
- 100 North Riverside Plaza· 874,519 sq ft · EUI 21.2 kBtu/ft²
- 10 South LaSalle Street· 871,962 sq ft · score 75 (B)
- Sullivan Center· 870,368 sq ft · score 80 (B)
- Office buildings in Chicago· 387 benchmarked
- All Chicago benchmarked buildings· Building Energy Use Benchmarking Ordinance
- Most efficient large buildings in Chicago
- Least efficient large buildings in Chicago
- Biggest emitters in Chicago
Frequently asked questions
What is One South Dearborn's energy grade?
One South Dearborn scores 81 out of 100 on ENERGY STAR — band B, above median (70–84) — in its 2023 Chicago disclosure. Scores are national percentiles against similar buildings; 75+ qualifies for ENERGY STAR certification.
How much energy does One South Dearborn use?
Its 2023 site energy-use intensity was 41.9 kBtu/ft² (117.4 kBtu/ft² source) across 942,732 sq ft, including 11,588,682 kWh of electricity.
What are One South Dearborn's carbon emissions?
One South Dearborn reported 5,533 tCO₂e of greenhouse-gas emissions (5.9 kgCO₂e/ft²) for 2023.
Where is One South Dearborn?
One South Dearborn is at 1 South Dearborn, in Chicago, Illinois 60603. Its coordinates are 41.88003, -87.65938 (latitude, longitude), as published in the Chicago Energy Benchmarking file.
How big is One South Dearborn and when was it built?
One South Dearborn has 942,732 sq ft of gross floor area, as reported in its 2023 disclosure. The disclosure lists 2005 as its year built. It is classed as office.
Is One South Dearborn covered by the Building Energy Use Benchmarking Ordinance?
Yes — it appears in the 2023 Chicago Energy Benchmarking disclosure, which lists the buildings reporting under the Building Energy Use Benchmarking Ordinance.
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About this data
Source: Chicago Energy Benchmarking (Building Energy Use Benchmarking Ordinance), as published October 2, 2026. See the methodology for how records are matched, cleaned and scored.
Cite as: BuildingCensus, “One South Dearborn, Chicago, Illinois — 2023 benchmarking disclosure”, https://buildingcensus.com/buildings/chicago/one-south-dearborn-4d2f8508 (data as of October 2, 2026).