NYC Rowhouse Retrofit Inventory
Every high-performance, deep-energy retrofit of a New York City rowhouse we have been able to find, and an open request for the ones we have missed.
Add your projects to the inventory.
Nothing personal will be published.
If you designed, built, modeled, certified, or consulted on a high-performance retrofit of a rowhouse/brownstone/townhouse in the five boroughs, it is likely missing from published lists. We want this inventory to bridge that gap.
Request the datasetThe redacted inventory as a spreadsheet, sent to everyone who asks at the end of October, 2026. Get updatesOccasional notes from reBuild on rowhouse retrofits and this inventory.
reBuild will never publish a street address, a block-and-lot, or an owner's name. Locations appear only as a ZIP code — and only where a ZIP holds three or more projects. A firm can be credited without its project being located, and a named party to any project can have its record reduced or removed on request.
A floor, not a census
Fifty-eight is everything we could find across registries, aggregators, press, and nine firms' own project lists. It is a count of what is visible, not of what exists.
Nine firm websites alone turned up 36 New York Passive House projects that no public aggregator listed, roughly doubling the rowhouse-retrofit count. One firm's direct list showed 16 certified rowhouse retrofits, of which only seven appear in the PHI database and none in Phius. The registries miss certified work, not just uncertified work. Every published count, including ours, is a floor.
Concentrated, not diffused
Of the 45 projects whose ZIP code is known, 26 sit in five ZIP codes — and 19 of those in three adjoining Brooklyn neighborhoods: Brooklyn Heights–Cobble Hill, Carroll Gardens–Red Hook, and Park Slope. Everything else is reported at borough level.
ZIP-level counts are published only where a ZIP holds three or more projects. Below that, a ZIP code combined with a completion year and a performance standard identifies a specific house to anyone who knows the neighborhood, so those records are reported by borough.
Certification is the wrong test
Certification signal, as stated by the source
Completion year, where known
Sources consulted
Firms are credited by name only when they ask to be. If your practice's work is here and you would like it credited, use the form above and choose "Performance, Type, ZIP code & team credit."
Why there are no addresses here
These are private homes. An address published alongside a gut-renovation scope and a completion year is a statement about a specific family's house, and neither we nor the practitioner who submitted a record has the standing to publish it.
What counts, and how we looked
Inclusion
A residential rowhouse, brownstone, or townhouse in the five boroughs — attached, sharing party walls — undergoing a retrofit whose scope targets a whole-building envelope and systems intervention: continuous insulation, an air barrier, high-performance glazing, mechanical ventilation with heat recovery, and electrified heating. Certification is not required; uncertified deep retrofits are counted and are precisely the population certification databases cannot see. New construction and freestanding houses are excluded.
Sources searched
- Passive House Institute certified buildings database (retrieved August 2026)
- Phius certified project database (retrieved August 2026)
- New York Passive House member case studies
- CityRealty and Green Map NYC project lists
- Nine practitioner websites, plus one firm's complete project list supplied on request
Known limits
A retrofit that was never certified, never published, and never listed by its firm is invisible to every source above. We assume there are more of these than we found and have no way to estimate how many. Firm-website rows record what each firm claims; certification signals were checked against the registries where a match could be made, and several PHI matches remain probable rather than proven because PHI publishes no street addresses. Landmark status for some records was read from historic-district boundaries rather than verified against LPC records.
The denominator
The rowhouse stock figure of roughly 217,000 is Neil Freeman's 2016 count from NYC PLUTO, using six criteria: attached, no more than 25 feet wide, street wall at least 92% of frontage, one to four units, residential building class, six stories or fewer.