At a glance
51 First Street is a 1,274-square-foot office building in Cambridge, Massachusetts, built in 1988. In its 2024 Cambridge benchmarking disclosure it reported an ENERGY STAR score of 8 out of 100 (grade D), a site energy-use intensity of 98.3 kBtu/ft² and 9 tCO₂e of greenhouse-gas emissions. That score is higher than 2% of the 94 scored office buildings in Cambridge.
BEUDO · reporting year 2024
Benchmarking record
| Field | Value |
|---|---|
| ENERGY STAR score | 8 (band D) |
| Site EUI | 98.3 kBtu/ft² |
| Source EUI | 275.2 kBtu/ft² |
| GHG emissions | 9 tCO₂e |
| GHG intensity | — |
| Electricity | 36,698 kWh |
| Water use | 24 kgal |
| Gross floor area | 1,274 sq ft |
| Source record | cambridge:B1897:2024 |
The disclosure history
Year over year
| Year | Score | Δ | Site EUI | GHG emissions |
|---|---|---|---|---|
| 2024latest | 8 | -4 | 98.3 kBtu/ft² | 9 tCO₂e |
| 2023 | 12 | +6 | 89.0 kBtu/ft² | 8 tCO₂e |
| 2022 | 6 | ±0 | 106.9 kBtu/ft² | 10 tCO₂e |
| 2021 | 6 | -2 | 105.6 kBtu/ft² | 10 tCO₂e |
| 2020 | 8 | +3 | 99.9 kBtu/ft² | 9 tCO₂e |
| 2019 | 5 | -5 | 111.9 kBtu/ft² | 9 tCO₂e |
| 2018 | 10 | -4 | 96.4 kBtu/ft² | 9 tCO₂e |
| 2017 | 14 | +1 | 86.7 kBtu/ft² | 8 tCO₂e |
| 2016 | 13 | +1 | 88.3 kBtu/ft² | 8 tCO₂e |
| 2015 | 12 | 91.6 kBtu/ft² | 9 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
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Location
- Address
- 51 First Street
- City
- Cambridge
- State
- Massachusetts
- Coordinates
- 42.36900, -71.07810
Within ~1 km
Nearby benchmarked buildings
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- 50-60 Binney STscore —
Mixed Use Property · 532,739 sq ft
- 8-12 Museum Wayscore 88
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- 20 Child Streetscore 100
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- 222 Jacobs Streetscore —
Laboratory · 466,713 sq ft
See also: most efficient in Cambridge · biggest emitters
How does 51 First Street compare with other office buildings in Cambridge?
The latest disclosures cover 117 office buildings in Cambridge, out of 902 buildings citywide. 51 First Street's ENERGY STAR score of 8 compares with an average of 64 across the 94 that report a score; it scores higher than 2% of them and lower than 96%. Its site EUI of 98.3 kBtu/ft² is about 25% above the average of 78.7 kBtu/ft² — it uses more energy per square foot than the typical building in that group.
At 1,274 sq ft, it is about 99% below the average floor area of 121,167 sq ft for those buildings. It was built in 1988, 23 years later 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 51 First Street's energy performance changed over time?
BuildingCensus holds 10 Cambridge disclosures for 51 First Street, covering report years 2015–2024. Its ENERGY STAR score went from 12 in 2015 to 8 in 2024 (-4 points); its best year on file was 2017, at 14. Site EUI moved from 91.6 kBtu/ft² (2015) to 98.3 kBtu/ft² (2024), an 7% increase. Reported emissions went from 9 tCO₂e to 9 tCO₂e over the same span (up 1%).
What does an ENERGY STAR score of 8 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 8 means the building performs better than about 8% of its national peers. BuildingCensus bands the score into report-card grades; 8 falls in band D — lowest band (1–54). It sits 67 points below 75, the threshold for ENERGY STAR certification. 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. 51 First Street's 98.3 kBtu/ft² across 1,274 sq ft works out to about 0.1 billion Btu (37 MWh-equivalent) in 2024. Its source EUI of 275.2 kBtu/ft² also counts the energy lost generating and delivering that power, which is why it is higher. The disclosure also reports 36,698 kWh of electricity and 24 thousand gallons of water for the year.
Which law requires 51 First Street to report its energy use?
51 First Street 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:B1897:2024). 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 office buildings in Cambridge
Frequently asked questions
What is 51 First Street's energy grade?
51 First Street scores 8 out of 100 on ENERGY STAR — band D, lowest band (1–54) — in its 2024 Cambridge disclosure. Scores are national percentiles against similar buildings; 75+ qualifies for ENERGY STAR certification.
How much energy does 51 First Street use?
Its 2024 site energy-use intensity was 98.3 kBtu/ft² (275.2 kBtu/ft² source) across 1,274 sq ft, including 36,698 kWh of electricity.
What are 51 First Street's carbon emissions?
51 First Street reported 9 tCO₂e of greenhouse-gas emissions for 2024.
Where is 51 First Street?
51 First Street is in Cambridge, Massachusetts. Its coordinates are 42.36900, -71.07810 (latitude, longitude), as published in the Building Energy Use Disclosure Ordinance (BEUDO) file.
How big is 51 First Street and when was it built?
51 First Street has 1,274 sq ft of gross floor area, as reported in its 2024 disclosure. The disclosure lists 1988 as its year built. It is classed as office.
Is 51 First Street 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, “51 First Street, Cambridge, Massachusetts — 2024 benchmarking disclosure”, https://buildingcensus.com/buildings/cambridge/51-first-street-3216b483 (data as of October 2, 2026).