At the Harlem River Houses, HVAC gets a history lesson

Two bright murals line the walls in the porticos leading into the Harlem River Houses, located in Manhattan between East 151st and 153rd Street. The eastern hallway features historic figures from Harlem’s past, like Malcolm X and Afeni Shakur, while the western hallway has some other familiar faces — of neigh­bors who walked these spaces throughout their lives, trans­posed on tinier bodies. Walter, a decades-long main­te­nance worker and resi­dent, is also shown: ​“He’s next to the famous folks, because he’s famous here,” Jacqueline Ortiz, an assis­tant general manager, pointed out on a recent walk there.

The artworks were part of a larger reno­va­tion project that wrapped this fall, which also saw major energy effi­ciency improve­ments thanks to modern­ized windows, energy-saving LED lighting, new HVAC systems, and more. Like most NYCHA build­ings, Harlem River Houses, or HRH, as it’s some­times short­ened to, has its own compli­ance stan­dards to meet for Local Law 97 (LL97), which requires build­ings of this size to meet new green­house gas emis­sions goals or face fines. The complex presented a partic­u­larly unique case for updating infra­struc­ture to get there: As New York City’s oldest feder­ally-funded public housing project, it was the first major retrofit in decades. 

The challenge: Future-proofing history

The orig­inal Houses, which opened in 1937, are made up of 574 apart­ments spread across nine acres. (An addi­tion with 116 addi­tional units was built in the 1960s, named Harlem River II.) Built at a time when public housing was racially segre­gated, HRH was an exper­i­ment in ​“sepa­rate but equal” public housing stan­dards. The complex was built for Black resi­dents at the same time as the majority-white Williamsburg Houses were built in Brooklyn, both funded by federal dollars through the Works Progress Administration. HRH has gone on to become a bastion for the city’s uptown Black commu­ni­ties — a repu­ta­tion the staff there proudly touts today.

Modernizing the NYCHA complex’s clus­ters wasn’t without chal­lenges. The largest, perhaps, was due to that history: In 1975, the entire campus was granted land­mark status, an honorific that has since height­ened as HRH has been cited as an acclaimed example of large-scale devel­op­ment. But the city’s land­mark laws also set strict rules around what alter­ations may be made. So any fixes put in had to be both precise and prac­tical — and in a city whose housing stock is, on average, 90 years old, their proven success could provide a stress-test for over­coming one of the greatest hurdles in decar­bonizing New York City: Age.

Undertaking an energy upgrade

Skylight got a tour of HRH, including a peek into a newly refur­bished unit. The whole suite of upgrades, both infra­struc­tural and cosmetic, have led to a higher quality of living for resi­dents; but for Manuel Ortiz (no rela­tion to Jacqueline), a super­in­ten­dent who has lived here for years, the most signif­i­cant aspect of the reno­va­tion is hidden to most. 

Until recently, the heating at HRH was powered by a dual fuel boiler that produced steam heat and domestic hot water for the entire campus. The older build­ings orig­i­nally had coal-burning boilers, but the whole devel­op­ment was converted to a steam piping system in the 1960s. The boiler was then powered by fuel oil and, even­tu­ally, natural gas. But the infra­struc­ture, now over sixty years old, had reduced energy effi­ciency, and contributed to green­house gas emis­sions that degraded air quality. These factors led the campus to emit more than 7,000 metric tons of carbon annu­ally, and earn a D energy effi­ciency letter grade, according to an energy audit report conducted by Bright Power. 

“Back in the day, when you got past the first three steps on that stair­case, you could feel heat,” said Manuel Ortiz, as we stepped into the base­ment, whose tunnels run under­neath, connecting the sepa­rate build­ings. ​“It looked like a boiler room from a horror movie down here. There were old chains and lifts everywhere.”

Under the new system, heating and cooling is local­ized and elec­tri­fied, with a vari­able refrig­erant flow (VRF) system; heat pumps on the roof pull in air from outside, then use refrig­erant to warm or cool the air, depending on the season, and blow it into ducted units in each apartment. 

The new system is not fully decen­tral­ized but, rather, dispersed — so if, say, one condenser blows, it’ll mini­mize the impact, limiting fallout to a single building instead of an entire system. The rain and cold outside during Skylight’s visit was a good reminder of why every degree of warmth matters. ​“From here, it tells me what the water temper­a­ture is, and what the apart­ment ther­mo­stat is showing,” said Ortiz, showing off the subter­ranean devices. ​“So while heat is flowing out of here, it lets me know how much heat is in the actual apart­ment upstairs.” 

Plus, it saves space: Today, the base­ment is brighter than before, with room for the staff to have meet­ings and workout equip­ment — a far cry from what once was.

Over at Harlem River II, package terminal heat pumps, other­wise known as PTHP units, were installed in every apart­ment to replace its steam heat system. This devel­op­ment is not under land­mark status, and thus carried fewer work restric­tions. The project at HRII also included a refur­bished roof and an Exterior Insulation and Finish System (EIFS) on the façade, which added insu­la­tion to retain heat. 

The elec­trical wiring, if anything, is more confined now but still exten­sive, as the PTHP units require more elec­trical load than the apart­ments were orig­i­nally designed for, said Ryan Esparza, an asso­ciate at Curtis + Ginsberg Architects. ​“So if there’s a two bedroom apart­ment, then there are three of these PHTP units in that apart­ment — one for each bedroom, and one for the living room,” he said. The archi­tects coor­di­nated with Con Edison to add more elec­trical capacity to the building, and addi­tional elec­trical risers, or shafts to carry elec­trical cables verti­cally across floors, were added to meet this addi­tional load, but even those were done as a clever repur­pose — the elec­trical risers were installed in corners where steam risers had previ­ously been. And another silver lining: All of this was done without having to rip up the street outside, like it must be for so many retrofits.

The heat pumps are limited to HRII since they impact the look of the façade, which a land­mark desig­na­tion bars. But Esparza is hopeful that its success will convince poli­cy­makers to soon consider it. ​“That’s not to say that they won’t at some point,” he said. ​“But hope­fully in the near future, you can use this in the building, and have some alter­nate tech­nology for those [build­ings with historic façades].”

But the heat pumps’ track record thus far has convinced the archi­tects to go beyond HRH.

“We’re now trying to push PTHP instal­la­tion at most of our projects, because it’s really a big step in the right direc­tion,” Esparza added. ​“We’re reducing how much refrig­erant exists within each building, so you don’t have long runs of piping from the rooftop to each unit. The poten­tial for leaks and the green­house gas emis­sions are just much less. And it’s a far easier system to install.”

All of these effi­ciency improve­ments are expected to lead to a 55 percent improve­ment in HRH’s carbon emis­sions, and bring both sites in compli­ance with LL97 through at least 2034, according to Bright Power’s projections. 

Paving a new path for HRH

All of these upgrades carried a steep shared price tag of $275 million. Specifically, upgrading to VRF at the orig­inal site cost about $16.5 million, and the PTHPs and over­cladding at HRH II cost about $4.68 million. 

The projects were made more afford­able through the Permanent Affordability Coming Together (PACT) program, which the city first created in 2016 as a way to bring in private and non-profit dollars into public housing explic­itly for reno­va­tions. When a public housing complex enters into a PACT agree­ment, the infu­sion of cash can mean a complete depar­ture from NYCHA’s norm. That is on display the minute one enters HRH. The red bricks have been restored. Statues have been buffed. And the manage­ment office is of a quality befit­ting a market-rate condo or co-op.

All of this is evident in the ground floor apart­ment, which the manage­ment team keeps empty in case tenants need to be temporarily relo­cated: The windows are newly weath­er­ized; the rattling steam radi­a­tors, staples of NYCHA units, have been swapped out for ther­mostats; most appli­ances, including the stove, are now elec­tric; and the flooring has a sleek aesthetic. 

A new Harlem River Houses, but still home

All of these changes offer an encour­aging new perspec­tive on what public housing can and should look like. In fact, the reno­va­tions have earned HRH recog­ni­tion among many of its peers in the world of archi­tec­ture and design — the reno­va­tion was awarded a 2025 Residential Design Award of Excellence by Docomomo US, a non-profit orga­ni­za­tion that high­lights conser­va­tion of build­ings, sites and neigh­bor­hoods of the modern movement. 

Yet the most salient impact of the new-and-improved HRH is for the people who call it home. Those changes begin with its new orga­ni­za­tional structure. 

HRH is now over­seen by the Settlement Housing Fund, a nonprofit that holds a 99-year lease on the land from NYCHA, which still owns the prop­erty; West Harlem Group Assistance, a commu­nity-based orga­ni­za­tion, was brought on to lead social services; and a sepa­rate subsidiary, C+C, handles management.

Assistant general manager Jacqueline Ortiz works for that last entity, and while it may appear a bit balka­nized, she said the new setup allows for a faster and easier approach to tenant concerns than before. ​“We’re constantly working with the developer’s engi­neering teams, who’s on the construc­tion side,” she explained. ​“So if a specific unit is affected by some­thing, we can quickly move neighbors.”

That came in handy when resi­dents were relo­cated else­where within HRH for six weeks as the energy effi­ciency repairs were underway. Complaints weren’t completely avoided then, and they still exist as neigh­bors accli­mate. ​“We’ve heard from people who miss the old radi­a­tors, but once they learn the ther­mo­stat, they love it,” Ortiz added.

But what matters most is the actual listening. At the end of Skylight’s tour, Tyrone Thomas, the general manager of HRH, stepped out of a morning meeting with his team to talk. For anyone consid­ering a similar retrofit, he stressed the impor­tance of having on-site social services. Transitions can be diffi­cult, and so offering a helping hand was crucial to ensuring that nobody was left behind in moving forward.

“We had town halls every month, and that really made a differ­ence,” said Thomas, as the day’s work — rent payments, work requests, etc. — got going. ​“By hearing from them, we got hands-on because there are things that we may not be aware of.”

“We’re still NYCHA, that’s the thing,” Jackie Ortiz commented. ​“But better living.”

Reporting contributed by Natasha Ishak. 

Corrections (Jan. 14, 2026): A previous version of this article misstated the total cost of the reno­va­tion project, and erro­neously attrib­uted it to another project as well. $275 million was spent on the project at Harlem River Houses only. This article also previ­ously misstated how the elec­trical wiring for the PTHP units at HRII was installed. We regret the errors.