Gradient’s heat pumps get new smarts to enable old-building retrofits

New York City and others like it are filled with old buildings that are for the most part fine, except they’re not all that comfortable to live in. Built in an era when massive boilers were cutting-edge technology, the buildings are usually too hot or too cold, but seldom just right.

There are companies trying to rectify that using clever horseshoe-shaped heat pumps. Superficially, they’re similar to window air conditioners, except they don’t block the view and they can heat as well as cool. 

Gradient makes one of those heat pumps, but now it’s adding a twist: In multifamily buildings, it can link every one of its window units together. The startup shared with TechCrunch exclusive details about the new Nexus software and service.

“Multifamily buildings are an ignored sector,” Vince Romanin, chief technology officer at Gradient, told TechCrunch. “It’s a place where we can do better for the user.”

The startup is mostly targeting old buildings that need HVAC upgrades. Gradient has worked with the New York City Housing Authority to install its heat pumps in public housing, and it ran a pilot in Tracy, California, in a newer two-story affordable-housing complex. It’s also talking with colleges and universities, many of which have dorms that weren’t built with hot autumn weather in mind.

Old buildings often have one electric meter, which can tempt residents into overusing their heating or air conditioning. Nexus gives some control back to building managers. They can set guardrails to prevent people from overusing the heat or AC — either intentionally or otherwise — while still allowing them to be comfortable. In one instance, a building manager set the heating limit at 78˚ F, and the next day energy consumption dropped by a quarter.

Romanin said Gradient’s heat pumps are the “lowest-cost option” for old buildings with boilers that are reaching end of life, a common occurrence in New York City. As a bonus, units that previously only had a steam radiator now get air conditioning, future proofing the units against worsening heat waves. 

By installing a window unit rather than a minisplit, retrofits can happen within hours. They also don’t require electrical upgrades, Romanin said. In buildings with old electrical wiring that can’t support a full 12 amp load on a single outlet, Nexus can reduce the draw, said Mansi Shah, senior vice president of product and software at Gradient.

That strategy can extend beyond the building too. When the grid is overwhelmed by demand, which can happen on hot summer days, Gradient is working on a way to dial back its heat pumps while still maintaining occupant comfort. By using information about the building along with feedback from sensors in the heat pumps, the company hopes to predict which units can reduce their air conditioning demand, like those on the shady side of a building. That sort of demand response can help the grid serve more heat pumps without requiring costly upgrades.

“There’s a lot of people who said when we electrify everything, the grid won’t handle it,” Romanin said. “I think that it is very possible to electrify everything and make the grid better, make the grid’s job easier, and make electrons cheaper.”