120 Howard St
120 Howard St is a 12-story building in Downtown San Francisco with 77% of its floor area within daylight reach of a facade. This screen estimates 171 homes and scores it 72 out of 100 for office-to-residential conversion suitability.
CA-11 · Screened 2026-10-12 · Strong candidate
Also addressed as 170 Spear St, 180 Spear St, 188 Spear St and 190 Spear St: San Francisco’s address records place all 5 on this one footprint.
Where 120 Howard St is
Its block in Downtown San Francisco, drawn from San Francisco's own building outlines and street centerlines.
- Already housing
- Not screened
- 120 Howard St
This building does not pencil at default assumptions, even with a modeled RESIDE Act grant.
Every floor carries 4,466 sq ft of windowless core — area that must be gutted, seismically braced and sprinklered but can never be rented as an apartment. Across 11 residential floors that is 49,126 sq ft of cost carrying no revenue.
Modeled conversion metrics for 120 Howard St, 2026-10-12.
| Suitability scoreStrong candidate | 72 / 100 |
|---|---|
| Storiesfrom 162 ft LiDAR (2010) height ÷ 12 ft floor-to-floor | 12 |
| Floor plateper floor, from the city footprint | 19,120 sq ft |
| Daylight efficiencyshare within 35 ft of a facade | 77% |
| Deepest interior pointviability threshold is 80 ft | 60 ft |
| Windowless coreper floor — renovated but never rentable | 4,466 sq ft |
| Estimated homesat 750 sq ft average | 171 |
| Conversion cost$405/sq ft all-in on 210,315 sq ft | $85.2M |
| Gap before grantshortfall against completed value | $22.6M |
| Modeled RESIDE grantat the statutory per-award cap | $10.0M |
| BuiltSan Francisco's own record of the construction year | 1973 |
| ZoningFinancial District/South Beach | C-3-O(SD) |
| Opportunity Zonenot in a 2018 designated tract | No |
The plan: window line, shape and floor rhythm
36 ft of exterior wall for each home the screen estimates — enough for two- and three-bedroom homes across the plan.
The typical floor has 552 ft of exterior wall, and across 11 residential floors the building carries 6,073 ft of it in total, divided among the 171 homes this screen estimates.
Its plate is compact at 0.79: close to a square or a circle, the most efficient envelope an office can have and the least generous one for apartments: little perimeter to divide among homes. How window line and plate shape are measured.
At the model’s 750 sq ft average, the plan works out at about 15.5 homes per floor, repeated on every residential floor, since this building's outline does not change as it rises.
Why 120 Howard St scores 72 out of 100
Daylight efficiency 73, Interior depth 51, Scale 100, Finance 75 — each out of 100, then weighted.
Score components for 120 Howard St. Points are the subscore times its weight.
| Component | Subscore | Weight | Points |
|---|---|---|---|
| Daylight efficiency77% of the floor area within 35 ft of a facade, scored from 40% up to 90% | 73 | 45% | 33.0 |
| Interior depthdeepest interior point 60 ft from a facade, scored from 80 ft down to 40 ft | 51 | 25% | 12.6 |
| Scale171 estimated homes, scored from 0 up to 150 | 100 | 15% | 15.0 |
| Financeremaining gap is 15% of conversion cost, scored from 60% down to 0% | 75 | 15% | 11.3 |
Most of what it earns comes from daylight efficiency, and what holds it back most is interior depth, at 51 out of 100: deepest interior point 60 ft from a facade, scored from 80 ft down to 40 ft.
Built in 1973
San Francisco records this building as going up in 1973, which puts it in the late-modern stock.
As a rule, typically the hardest to convert: the deepest plates of any era, large central cores, and floor-to-floor heights tight enough that running residential drainage under a ceiling can be the thing that ends a project. That is the era’s general tendency rather than a finding about this building — the model reads an outline and a height, and can see nothing inside — but it is the first thing an architect would want to know, and it colours how much confidence the 77% daylight figure above deserves.
What the conversion would cost
$405 per square foot all-in across 210,315 sq ft of converted floor, or $85.2M in total — about $498K for each of the 171 homes.
All-in cost per square foot for 120 Howard St: base cost plus the code work a change of use triggers.
| Base conversion cost | $260/sq ft |
|---|---|
| Seismic retrofit (change of use) | $45/sq ft |
| Plumbing risers to every unit | $40/sq ft |
| Operable windows and glazing | $30/sq ft |
| Additional egress stair | $18/sq ft |
| Fire sprinklers (NFPA 13R) | $12/sq ft |
| All-in | $405/sq ft |
That cost is charged across every converted square foot, including the 49,126 sq ft of windowless core, which has to be gutted, seismically braced and sprinklered like the rest of the building and then earns nothing. Against it the model sets a completed value of $366K a home, which for 171 homes is $62.6M.
What would have to be true
A $22.6M gap before any grant, $12.6M after the modeled one. The smallest single change that would close it: average unit size 17% down.
The shortfall before any grant is $22.6M. Closing it from the value side means each of the 171 homes finishing at $498K rather than the $366K the model assumes — 36% more. Closing it from the cost side means getting all-in cost down from $405 to $298 per square foot.
A modeled RESIDE grant of $10.0M moves that threshold to $440K a home. That is still above the $366K assumed, leaving $12.6M uncovered, which is why the grant does not unlock this one.
Nor do all four levers have to move. For 120 Howard St, one alone would close the gap at:
Single-assumption flip points for 120 Howard St, each holding the other three at their defaults.
| Average unit sizethe binding constraint — the least this building would need | 17% downto 626 sq ft |
|---|---|
| Circulation efficiency | 20% upto 96% |
| Completed value per home | 20% upto $440K |
| Conversion cost per square foot | 23% downto $200/sq ft |
All four are sliders in the survey, where 120 Howard St re-scores against your own numbers.
How it compares in Downtown San Francisco
120 Howard St ranks 141st of the 205 buildings screened here, against a median score of 87.
Its floor plate is better lit than 25% of them, and shallower than 30% of them at its deepest interior point. On size it is the 95th largest by estimated homes. The full survey of all 205 buildings ranks and maps every one of them, and the list by address links each to its own page.
Within Financial District/South Beach and the C-3-O(SD) zone
115th of 165 in Financial District/South Beach, 33rd of 66 zoned C-3-O(SD) — the comparison that shares its rules, rents and streets.
San Francisco places 165 of the screened buildings in Financial District/South Beach. 120 Howard St ranks 115th of them against a median score of 88. 121 score 70 or more, their median deepest interior point is 47 ft from a facade against this building’s 60 ft, and together they would hold an estimated 40,456 homes. The group’s top scorer is 870 Market St, at 100.
66 of the screened buildings are zoned C-3-O(SD). 120 Howard St ranks 33rd of them against a median score of 72. 37 score 70 or more, their median deepest interior point is 59 ft from a facade against this building’s 60 ft, and together they would hold an estimated 18,546 homes. The group’s top scorer is 140 New Montgomery St, at 100.
Its nearest match in size: 180 Howard St
The screened building closest to 120 Howard St in converted floor area is 180 Howard St: 218,210 sq ft over 13 stories, against 210,315 sq ft over 12 here.
120 Howard St scores 72 to its 67, and with the size held roughly equal most of that lead comes from interior depth: 51 out of 100 here, 32 there (deepest interior point 67 ft from a facade, scored from 80 ft down to 40 ft). On the money they sit in the same place: each falls short even with the modeled grant. The two stand about 100 ft apart.
Would it qualify for a RESIDE Act grant?
The model awards 120 Howard St $10.0M, on the assumption it qualifies. Whether it does, no published dataset can say.
That figure assumes the building meets the Act’s vacant-and-abandoned test, which turns on code-enforcement and receivership records no city publishes.
It does not sit in a 2018 designated Opportunity Zone, so it would not draw that Section 201 priority.
Other buildings screened near 120 Howard St
The 4 closest the screen also covers, from 150 ft away. They are the colored outlines on the plan at the top of this page.
- 180 Howard St13 stories · 77% daylit · 178 estimated homes · scores 67/100 (Worth a feasibility study)about 150 ft away
- 155 Main St19 stories · 83% daylit · 244 estimated homes · scores 81/100 (Strong candidate)about 200 ft away
- 150 Spear St18 stories · 83% daylit · 234 estimated homes · scores 79/100 (Strong candidate)about 220 ft away
- 101 Howard St5 stories · 78% daylit · 57 estimated homes · scores 62/100 (Worth a feasibility study)about 230 ft away
A screen, not a feasibility study, from outlines and heights rather than plans: the method and how to correct a figure. If you know this building’s interior, you know what this model cannot see.