NYC's insulation gap, in numbers.
We aggregated every residential tax lot in New York City with five or more apartments — all 73,637 of them. Three findings stand out: most of the city's multifamily stock predates insulation codes, its top-floor roof area is measured in the hundreds of millions of square feet, and at published utility rates the incentives to fix it run into ten figures.
73,637
Buildings with 5+ units
74%
Built before 1940 (avg. 1936)
359M
Sq ft of top-floor roof area*
$1.44B–$1.79B
Illustrative incentive at $4–5/sq ft*
Where the buildings — and the money — are.
| Borough | 5+ unit buildings | Apartments | Pre-war share | Roof area (sq ft)* | Illustrative incentive* | Gas utility |
|---|---|---|---|---|---|---|
| Brooklyn | 28,769 | 668,947 | 75% | 112,611,192 | $450M–$563M | National Grid |
| Manhattan | 22,588 | 931,083 | 84% | 95,847,175 | $383M–$479M | Con Edison |
| Queens | 11,818 | 431,700 | 58% | 76,723,254 | $307M–$384M | Split (NG south / Con Ed north) |
| The Bronx | 9,757 | 454,782 | 72% | 64,621,867 | $258M–$323M | Con Edison |
| Staten Island | 705 | 31,969 | 33% | 9,091,287 | $36M–$45M | National Grid |
*ROOF AREA IS BUILDING AREA ÷ FLOORS (A TOP-FLOOR-CEILING PROXY FROM NYC PLUTO), NOT MEASURED ROOF POLYGONS. INCENTIVE FIGURES APPLY THE PUBLISHED $4–5/SQ FT ENVELOPE RATE TO THAT AREA — AN ILLUSTRATIVE THEORETICAL MAXIMUM IF EVERY BUILDING PARTICIPATED, NOT A STATEMENT OF ANY PROGRAM'S ACTUAL BUDGET. ELIGIBILITY DEPENDS ON THE GAS UTILITY, HEATING FUEL, EXISTING CONDITIONS, AND PROGRAM CYCLE.
Three of four buildings predate insulation codes.
54,838 of the city's 73,637 five-plus-unit buildings — 74% — were built before 1940, decades before New York required insulation in new construction. Brooklyn alone holds 21,662 pre-war multifamily buildings. Most still have an uninsulated top-floor ceiling under a flat roof: the single largest heat loss in the building, and the exact measure utility programs pay the most to fix.
In National Grid's gas territory alone — Brooklyn and Staten Island, before counting southern Queens — that's 29,474 buildings and an illustrative $487M–$609M at published rates.
Check one building freeMethod & reuse
Cite freely — with a link.
Figures were computed September 1, 2026 from NYC PLUTO via Socrata aggregation: all residential tax lots with 5+ units, roof area approximated as building area ÷ floors, incentives at the published $4–5/sq ft envelope rate. Utility territory per Con Edison's service map.
Journalists, researchers, and bloggers may reuse these figures and tables under CC BY 4.0 — attribution to NationalGridRebate.com with a link to this page. Questions about the method: contact us.