45 Flagg St
At a glance
45 Flagg St is a 209,979-square-foot residence hall/dormitory in Cambridge, Massachusetts, built in 1970. In its 2024 Cambridge benchmarking disclosure it reported an ENERGY STAR score of 78 out of 100 (grade B), a site energy-use intensity of 72.3 kBtu/ft² and 1,026 tCO₂e of greenhouse-gas emissions. That score is higher than 37% of the 27 scored residence hall/dormitory buildings in Cambridge.
BEUDO · reporting year 2024
Benchmarking record
| Field | Value |
|---|---|
| ENERGY STAR score | 78 (band B) |
| Site EUI | 72.3 kBtu/ft² |
| Source EUI | 110.6 kBtu/ft² |
| GHG emissions | 1,026 tCO₂e |
| GHG intensity | — |
| Electricity | 909,830 kWh |
| Water use | 5,393 kgal |
| Gross floor area | 209,979 sq ft |
| Source record | cambridge:B1179:2024 |
The disclosure history
Year over year
| Year | Score | Δ | Site EUI | GHG emissions |
|---|---|---|---|---|
| 2024latest | 78 | +1 | 72.3 kBtu/ft² | 1,026 tCO₂e |
| 2023 | 77 | -1 | 71.3 kBtu/ft² | 1,012 tCO₂e |
| 2022 | 78 | -3 | 75.2 kBtu/ft² | 1,065 tCO₂e |
| 2021 | 81 | -3 | 70.3 kBtu/ft² | 997 tCO₂e |
| 2020 | 84 | +6 | 67.5 kBtu/ft² | 951 tCO₂e |
| 2019 | 78 | -2 | 77.0 kBtu/ft² | 1,071 tCO₂e |
| 2018 | 80 | +3 | 76.3 kBtu/ft² | 1,075 tCO₂e |
| 2017 | 77 | +1 | 75.9 kBtu/ft² | 1,085 tCO₂e |
| 2016 | 76 | ±0 | 75.0 kBtu/ft² | 1,075 tCO₂e |
| 2015 | 76 | 79.4 kBtu/ft² | 1,143 tCO₂e |
Compliance context
BEUDO
Cambridge's 2023 BEUDO amendments require non-residential buildings of 100,000+ sq ft to reach net-zero emissions by 2035 (reductions starting 2026) and those of 25,000–100,000 sq ft by 2050 (starting 2030).
Ownership
PRESIDENT & FELLOWS OF HARVARD COLLEGE
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Location
- Address
- 45 Flagg St
- City
- Cambridge
- State
- Massachusetts
- Coordinates
- 42.36820, -71.11530
Within ~1 km
Nearby benchmarked buildings
- 1 Bennet Streetscore 67
Hotel · 498,000 sq ft
- 900 Memorial Drivescore 47
Multifamily Housing · 450,849 sq ft
- 459 Broadwayscore 71
K-12 School · 403,393 sq ft
- 75 Mount Auburn Streetscore 79
Office · 345,571 sq ft
- 812 Memorial Drscore 99
Multifamily Housing · 283,150 sq ft
- 95 Dunster Stscore —
Residence Hall/Dormitory · 257,543 sq ft
See also: most efficient in Cambridge · biggest emitters
How does 45 Flagg St compare with other residence hall/dormitory buildings in Cambridge?
The latest disclosures cover 43 residence hall/dormitory buildings in Cambridge, out of 902 buildings citywide. 45 Flagg St's ENERGY STAR score of 78 compares with an average of 80 across the 27 that report a score; it scores higher than 37% of them and lower than 59%. Its site EUI of 72.3 kBtu/ft² is roughly in line with the average of 70.2 kBtu/ft².
At 209,979 sq ft, it is about twice the average floor area of 102,348 sq ft for those buildings. It was built in 1970, 54 years later than the group's average year built (1916). Across all 24 jurisdictions BuildingCensus covers, the 702 residence hall/dormitory buildings average an ENERGY STAR score of 70 and a site EUI of 70.7 kBtu/ft².
How has 45 Flagg St's energy performance changed over time?
BuildingCensus holds 10 Cambridge disclosures for 45 Flagg St, covering report years 2015–2024. Its ENERGY STAR score went from 76 in 2015 to 78 in 2024 (+2 points); its best year on file was 2020, at 84. Site EUI moved from 79.4 kBtu/ft² (2015) to 72.3 kBtu/ft² (2024), a 9% decrease. Reported emissions went from 1,143 tCO₂e to 1,026 tCO₂e over the same span (down 10%).
What does an ENERGY STAR score of 78 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 78 means the building performs better than about 78% of its national peers. BuildingCensus bands the score into report-card grades; 78 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 Cambridge, 50% 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. 45 Flagg St's 72.3 kBtu/ft² across 209,979 sq ft works out to about 15.2 billion Btu (4,449 MWh-equivalent) in 2024. Its source EUI of 110.6 kBtu/ft² also counts the energy lost generating and delivering that power, which is why it is higher. The disclosure also reports 909,830 kWh of electricity and 5,393 thousand gallons of water for the year.
Which law requires 45 Flagg St to report its energy use?
45 Flagg St reports under BEUDO, the legal basis of Cambridge's Building Energy Use Disclosure Ordinance (BEUDO), which publishes each covered building's annual benchmarking results. The record shown here is the report-year 2024 disclosure (source record cambridge:B1179:2024). Cambridge's 2023 BEUDO amendments require non-residential buildings of 100,000+ sq ft to reach net-zero emissions by 2035 (reductions starting 2026) and those of 25,000–100,000 sq ft by 2050 (starting 2030).
More residence hall/dormitory buildings in Cambridge
- 53 Bow Street· 203,985 sq ft · EUI 72.5 kBtu/ft²
- 64 Linnaean Street· 191,944 sq ft · EUI 67.8 kBtu/ft²
- 945 Memorial Dr· 189,856 sq ft · EUI 78.5 kBtu/ft²
- 100 Walker Street· 172,773 sq ft · EUI 50.0 kBtu/ft²
- 35-39 Oxford St· 74,264 sq ft · score 94 (A)
- 84-86 Brattle Street· 73,332 sq ft · score 41 (D)
- Residence Hall/Dormitory buildings in Cambridge· 43 benchmarked
- All Cambridge benchmarked buildings· BEUDO
- Most efficient large buildings in Cambridge
- Least efficient large buildings in Cambridge
- Biggest emitters in Cambridge
Frequently asked questions
What is 45 Flagg St's energy grade?
45 Flagg St scores 78 out of 100 on ENERGY STAR — band B, above median (70–84) — in its 2024 Cambridge disclosure. Scores are national percentiles against similar buildings; 75+ qualifies for ENERGY STAR certification.
How much energy does 45 Flagg St use?
Its 2024 site energy-use intensity was 72.3 kBtu/ft² (110.6 kBtu/ft² source) across 209,979 sq ft, including 909,830 kWh of electricity.
What are 45 Flagg St's carbon emissions?
45 Flagg St reported 1,026 tCO₂e of greenhouse-gas emissions for 2024.
Where is 45 Flagg St?
45 Flagg St is in Cambridge, Massachusetts. Its coordinates are 42.36820, -71.11530 (latitude, longitude), as published in the Building Energy Use Disclosure Ordinance (BEUDO) file.
How big is 45 Flagg St and when was it built?
45 Flagg St has 209,979 sq ft of gross floor area, as reported in its 2024 disclosure. The disclosure lists 1970 as its year built. It is classed as residence hall/dormitory.
Is 45 Flagg St covered by BEUDO?
Yes — it appears in the 2024 Building Energy Use Disclosure Ordinance (BEUDO) disclosure, which lists the buildings reporting under BEUDO.
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About this data
Source: Building Energy Use Disclosure Ordinance (BEUDO) (BEUDO), as published October 2, 2026. See the methodology for how records are matched, cleaned and scored.
Cite as: BuildingCensus, “45 Flagg St, Cambridge, Massachusetts — 2024 benchmarking disclosure”, https://buildingcensus.com/buildings/cambridge/45-flagg-st-1165fc94 (data as of October 2, 2026).