Longfellow Apartments

How does Longfellow Apartments compare with other multifamily housing buildings in Washington, DC?

The latest disclosures cover 1,799 multifamily housing buildings in Washington, DC, out of 6,870 buildings citywide. Longfellow Apartments's ENERGY STAR score of 69 compares with an average of 72 across the 1,618 that report a score; it scores higher than 36% of them and lower than 63%. Its site EUI of 76.6 kBtu/ft² is about 50% above the average of 51.1 kBtu/ft² — it uses more energy per square foot than the typical building in that group. Its emissions intensity of 4.7 kgCO₂e/ft² is about 24% above the group average of 3.8 kgCO₂e/ft².

At 66,288 sq ft, it is about half of the average floor area of 136,346 sq ft for those buildings. It was built in 1932, 33 years earlier than the group's average year built (1965). 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 Longfellow Apartments's energy performance changed over time?

BuildingCensus holds 7 Washington, DC disclosures for Longfellow Apartments, covering report years 2018–2024. Its ENERGY STAR score went from 42 in 2018 to 69 in 2024 (+27 points); its best year on file was 2020, at 75. Site EUI moved from 101.9 kBtu/ft² (2018) to 76.6 kBtu/ft² (2024), a 25% decrease. Reported emissions went from 338 tCO₂e to 313 tCO₂e over the same span (down 7%).

What does an ENERGY STAR score of 69 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 69 means the building performs better than about 69% of its national peers. BuildingCensus bands the score into report-card grades; 69 falls in band C — below median (55–69). It sits 6 points below 75, the threshold for ENERGY STAR certification. In Washington, DC, 47% 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. Longfellow Apartments's 76.6 kBtu/ft² across 66,288 sq ft works out to about 5.1 billion Btu (1,488 MWh-equivalent) in 2024. Its source EUI of 104.7 kBtu/ft² also counts the energy lost generating and delivering that power, which is why it is higher. The disclosure also reports 272,901 kWh of electricity, 38,087 therms of natural gas and 4,389 thousand gallons of water for the year.

Which law requires Longfellow Apartments to report its energy use?

Longfellow Apartments reports under the Clean and Affordable Energy Act / BEPS, the legal basis of Washington, DC's Building Energy Benchmarking program, which publishes each covered building's annual benchmarking results. The record shown here is the report-year 2024 disclosure (source record dc:PM10288675:2024). DC's Building Energy Performance Standards (BEPS) require buildings below the performance standard to improve over compliance cycles (the first ends December 31, 2026; later cycles run five years), with penalties for buildings that fail to meet their pathway.