150 Tremont St

150 Tremont St is a 22-story condominium building in Downtown Boston. Its floor plate has 89% of its area within daylight reach of a facade and scores 99 out of 100 on this screen’s measures, which is part of why it works as housing.

MA-7 & MA-8 · Screened 2026-10-04 · Already housing

Also addressed as 151 Tremont St: Boston’s address records place both on this one footprint.

Where 150 Tremont St is

Its block in Downtown Boston, drawn from Boston's own building outlines and street centerlines.

Suitability score

0–29

30–49

50–69

70–100

Already housing
Not screened
150 Tremont St

150 Tremont St and the 1,000 ft of Downtown Boston around it. The streets are drawn at the width of the right-of-way they run down, sidewalks included, and named, and every building on these blocks is drawn. What is left open and stippled is neither: a surface lot, a plaza or a vacant parcel. The screened buildings are colored by the ramp above, the same one the district map uses, carry their score, and each is a link to its own page. Each casts a shadow as long as its measured height lets it, so towers stand out from the low buildings around them; the unscreened buildings have no measured height and cast none. 150 Tremont St is outlined in its own score color at the outline it covers at ground level. Dashed inside it is the typical floor, the one the floor-plate figure below draws, because this building steps back as it rises. Its windowless core is hatched. The inset places it among every building the screen covers.

Typical floor plan: 89% of the building’s floor area sits within daylight reach of a facade; the drawing shows its typical floor, where the share is 100%. The shading is daylight, darkest at the windows and gone 35 ft in. The hatched area is windowless core: 33 sq ft per typical floor that must be renovated but can never be rented as an apartment. The dimension marks the deepest interior point, 35 ft from the nearest window. A–A is where the section beside it is cut.

Section A–A: cut across the depth of the plate, through the middle of the core. Daylight reaches 35 ft in from every facade, fading as it goes, and the hatched stripe left between the lit edges is floor that gets converted and can never be rented: 33 sq ft on the floor the screen scores, and 63,437 sq ft over 21 residential floors. The steps are where the building sets back as it rises. The shaded ground floor is converted like the rest and counted as no homes.

This is already a condominium building: Boston's assessing records list 372 condominiums here. It is on the map because a record on the same parcel carries an office land-use code, but this site does not count it as a conversion candidate.

Across its 21 residential floors this building carries 63,437 sq ft of windowless core — area that must be gutted, re-plumbed and sprinklered but can never be rented as an apartment.

Modeled conversion metrics for 150 Tremont St, 2026-10-04.

Suitability scoreStrong candidate	99 / 100
Storiesfrom 266 ft aerial-survey height ÷ 12 ft floor-to-floor	22
Height bandsfloor plate by floor range, from the city's roof outlines	Floors 1–5: 40,652 sq ft · Floors 6–10: 35,197 sq ft · Floors 11–20: 18,762 sq ft · Floors 21–22: 14,781 sq ft
Floor platetypical floor, from the city outlines	18,762 sq ft
Daylight efficiencyshare within 35 ft of a facade	89%
Deepest interior pointviability threshold is 80 ft	35 ft
Windowless coretypical floor; the building-wide total is in the text above	33 sq ft
BuiltBoston's own record of the construction year	1999
ZoningDowntown Boston	SKY-LOW-DT
Opportunity Zonenot in a 2018 designated tract	No

The plan: window line, shape and floor rhythm

34 ft of exterior wall for each home the screen estimates — enough for two- and three-bedroom homes across the plan.

The typical floor has 715 ft of exterior wall, and across 21 residential floors the building carries 17,898 ft of it in total, divided among the 525 homes this screen estimates.

Its plate is moderately compact at 0.46: a squarish plan, with enough perimeter for a conventional double-loaded corridor. How window line and plate shape are measured.

At the model’s 750 sq ft average, the plan works out at about 25.0 homes per floor. Its floors are not alike, though: the typical floor's deepest interior point is 35 ft from a facade, while its worst floor reaches 68 ft. The score follows the typical floor, so a podium that could not hold a bedroom does not by itself sink a slim tower above it — but it is there, and it is part of what would have to be drawn around.

Why 150 Tremont St scores 99 out of 100

Daylight efficiency 97, Interior depth 100, Scale 100, Finance 100 — each out of 100, then weighted.

Score components for 150 Tremont St. Points are the subscore times its weight.

Component	Subscore	Weight	Points
Daylight efficiency89% of the floor area within 35 ft of a facade, scored from 40% up to 90%	97	45%	43.7
Interior depthdeepest interior point 35 ft from a facade, scored from 80 ft down to 40 ft	100	25%	25.0
Scale525 estimated homes, scored from 0 up to 150	100	15%	15.0
Financecompleted value covers conversion cost with 21% to spare, which tops out the component	100	15%	15.0

Every component scores at or near full marks, so nothing in the geometry or the pro-forma is holding this one back — daylight efficiency carries the most weight of the four.

Built in 1999

Boston records this building as going up in 1999, which puts it in the modern stock.

As a rule, newer systems and better structure, but usually built deep and sealed for office use, and rarely cheap enough to buy at a price that lets a conversion pencil. 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 89% daylight figure above deserves.

Other buildings screened near 150 Tremont St

The 4 closest the screen also covers, from 260 ft away. They are the colored outlines on the plan at the top of this page.

25-31 West St
5 stories · 100% daylit · 31 estimated homes · scores 88/100 (Strong candidate)
about 260 ft away
60-70 Temple Pl
7 stories · 95% daylit · 50 estimated homes · scores 89/100 (Strong candidate)
about 560 ft away
28-38 Winter St
14 stories · 95% daylit · 106 estimated homes · scores 95/100 (Strong candidate)
about 630 ft away
1 Avenue De Lafayette
22 stories · 59% daylit · 721 estimated homes · scores 35/100 (Marginal)
about 650 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.