Gradient’s heat pumps have new intelligence to enable retrofits of older buildings

New York City and other similar cities are full of old buildings that are mostly good, but not comfortable to live in. Built in an era when huge boilers were cutting-edge technology, buildings were usually either very hot or very cold, but rarely quite right.

There are companies trying to correct this with smart horseshoe heat pumps. Superficially, they are similar to window air conditioners, except that they do not block the view and can heat and cool as well.

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

“Multifamily buildings are a neglected sector,” Vince Romanen, chief technology officer at Gradient, told TechCrunch. “It’s a place where we can give the best to the user.”

The startup mostly targets older buildings that need HVAC system upgrades. Gradient has worked with the New York City Housing Authority to install its heat pumps in public housing, and conducted a pilot in Tracy, California, in a modern two-story affordable housing complex. She’s also talking to colleges and universities, many of which have college housing that wasn’t built with hot fall weather in mind.

Older buildings often have only one electric meter, which may tempt residents to overuse heating or air conditioning. Nexus gives some control back to building managers. They can put up guardrails to prevent people from overusing heat or air conditioning — intentionally or otherwise — while still allowing them to rest. In one case, the building manager set the heating limit at 78°F, and the next day energy consumption was reduced by a quarter.

Romanin said Gradient heat pumps are the “lowest cost option” for older buildings with boilers that have reached the end of their life, which is common in New York City. As a bonus, units that previously had only a steam radiator now get air conditioning, protecting future units from worsening heat waves.

By installing a window unit instead of a mini-split, retrofits can be done in a matter of hours. It also doesn’t need electrical upgrades, Romanin said. In buildings with older electrical wiring that can’t support a full 12-amp load on a single outlet, Nexus can reduce draw, said Mansi Shah, senior vice president of products and software at Gradient.

This strategy can extend beyond the building as well. When the grid gets overwhelmed by demand, which can happen on hot summer days, Gradient works to find a way to turn its heat pumps back on while keeping occupants comfortable. By using information about the building along with feedback from sensors in the heat pumps, the company hopes to predict which units can reduce air conditioning demand, such as those on the shaded side of a building. This type of demand response can help the network serve more heat pumps without the need for costly upgrades.

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