1601 WALNUT ST

1601 WALNUT ST is a 15-story building in Center City Philadelphia with 95% of its floor area within daylight reach of a facade. This screen estimates 140 homes and scores it 92 out of 100 for office-to-residential conversion suitability.

PA-2 & PA-3 · Screened 2026-09-15 · Strong candidate

1601 WALNUT ST — 95% of each floor sits within daylight reach of a facade. The hatched area is windowless core: 448 sq ft per floor that must be renovated but can never be rented as an apartment. Deepest interior point: 39 ft from the nearest window.

This building does not pencil at default assumptions, even with a modeled RESIDE Act grant.

Every floor carries 448 sq ft of windowless core — area that must be gutted, re-plumbed and sprinklered but can never be rented as an apartment. Across 14 residential floors that is 6,272 sq ft of cost carrying no revenue.

Modeled conversion metrics for 1601 WALNUT ST, 2026-09-15.
Suitability scoreStrong candidate	92 / 100
Storiesfrom 195 ft LiDAR height ÷ 12 ft floor-to-floor	15
Floor plateper floor, from the city footprint	9,881 sq ft
Daylight efficiencyshare within 35 ft of a facade	95%
Deepest interior pointviability threshold is 80 ft	39 ft
Windowless coreper floor — renovated but never rentable	448 sq ft
Estimated homesat 750 sq ft average	140
Conversion cost$360/sq ft all-in on 138,332 sq ft	$49.8M
Gap before grantshortfall against completed value	$22.3M
Modeled RESIDE grantbelow the statutory cap	$8.4M
ZoningCenter City Philadelphia	CMX5
Opportunity Zonenot in a 2018 designated tract	No

These figures are a screen, not a feasibility study, and they come from public footprint and height data rather than from plans. See how this was computed and what it cannot tell you, or open this building in the interactive survey to change the assumptions behind it.