How an over-the-air update made Quilt’s heat pumps more powerful

Software might be eating the world, but it’s taking some industries longer than others to realize its full potential.

From iPhones to Teslas, people have grown accustomed to software updates improving the stuff they already own. But outside consumer electronics^[1] and automobiles^[2], over-the-air updates aren’t commonplace yet.

Yet that’s beginning to change, starting with an unlikely product: heat pumps. Last week, heat pump startup Quilt^[3] said that it pushed an update last week to heat pumps already installed in customers’ homes. It wasn’t just a bug fix either: the new software and firmware boosted the units’ heating and cooling capacities overnight by more than 20%.

“From the very beginning, we wanted to design the systems to be able to be continuously improved, updated over the air. It’s a pattern that’s happened in EVs and gotten a lot of traction, but no one had really done that before in HVAC,” Quilt CEO Paul Lambert told TechCrunch.

“In cars, sometimes they call it software-defined vehicles. We feel like we’ve created software-defined HVAC,” he added.

It can be hard to prove a negative, but according to heat pump expert Drew Tozer^[4], the update is likely the first of its kind. Typically, when a heat pump is installed — or any piece of HVAC equipment — the only time it’s touched is when there’s a problem.

But many on Quilt’s team^[5] didn’t come from a traditional HVAC background. Instead, they were drawn from Nest^[6], Google, Apple, and Tesla, companies where frequent updates are the norm. Isaac McQuillen, the engineer who led the capacity increase project, worked most recently at Lucid Motors, where he managed heating and cooling for both passengers and batteries.

“We got some feedback from both [installation] partners and some customers that it’d be really useful if we were able to have a slightly higher maximum operating capacity,” McQuillen said. Some people had larger living rooms or open floorpans that were more demanding. So the team dug in to see if the heat pumps had a little extra to give.

Quilt had specified more and higher quality sensors than what is normally found in residential HVAC systems, including additional pressures sensors, higher accuracy temperature and current sensors, McQuillen said. That data was key to the project.

Once the team realized they had room to spare, they set about testing the new parameters on in-house units to validate both performance and reliability. Quilt’s updates included both software and firmware that runs on the main processor and microcontrollers scattered throughout the indoor and outdoor units.

Originally installed, the outdoor portion of a Quilt heat pump provided up to 19,700 BTUs of cooling per hour and 20,500 BTUs of heating per hour. Now, cooling and heating figures have increased to 24,000 BTUs per hour and 25,200 BTUs per hour, respectively.

The new ratings don’t change how efficiently the heat pumps run, but it does allow them to better cope with extreme heat and cold. 

The power of over-the-air updating doesn’t come for free. It was only possible because Quilt had used higher quality sensors, monitored the data more closely, and included networking equipment to receive the update. They added a small amount to the total bill of materials, Lambert said. But as the company sees it, the benefits far outweigh the costs. “There’s the upfront capital cost of the sensors, but we think there’s just so much value to be gained from that extra data that that we felt that was worth it to integrate them,” McQuillen said.

”The hard part,” Lambert added, ”is knowing how to build all the integration around it with the software and all the systems working together.”

Plus, Quilt can now sell the units to a broader range of customers without having to design and market an entirely new model. Sounds like a win-win.