Chances are you’ve been there: Your formerly hot shower suddenly turns cold, darkening your mood in the process.
Maybe someone in your household took an extra shower or you did a few too many loads of laundry. It’s a classic case of supply not meeting demand. Michael Rigney thinks he can predict when a household will need more hot water, eliminating cold showers without turning to expensive alternatives like on-demand water heaters.
Rigney’s quest started a few years ago when he began researching water heating. What he saw “was really eye opening,” Rigney told TechCrunch in a recent interview.
The basic technology behind most water heaters, whether they’re gas or electric, hasn’t changed much in several decades. They might be cheap to buy, but they’re not cheap to run.
Heat pump water heaters have started to change that for many homeowners, improving efficiency and lowering utility bills. But even there, “I saw a tremendous opportunity for improvement,” Rigney said.
He founded Cala Systems in Boston in 2020 as heat pump water heaters were beginning to take off. Because of that shift, he said, “there was an entrepreneurial opportunity to build the best heat pump water heater.”
Water heaters tend to be fairly straightforward appliances: At their core, they have three basic parts: an insulated tank, a heating element and a thermostat. Most people set the temperature once and forget it; on rare occasions, they might set it a bit higher when overnight guests arrive. As hot water is drawn from the tank, cold water replaces it, driving down the temperature inside. When the temp gets low enough, the thermostat tells the heater to turn on.
“That’s really antiquated,” Rigney said. “We can do better in 2024.”
Cala Systems’ water heater pairs an advanced heat pump with an AI-powered control system to forecast hot water demand and heat the water in the tank accordingly. The company gathers general information like weather forecasts and time-of-use energy pricing and sends it to the water heater. That data is then analyzed on the device along with household specific information, including water usage patterns, incoming cold water temperature, and whether the home has solar panels. (Rigney said the company will never sell household data.)
By analyzing water use patterns, the tank can anticipate when there will be a surge in demand and heat the water in the most efficient way possible.
For example, if the weather is predicting a handful of sunny days before a couple days of clouds, Cala’s algorithms might decide to use daytime power from a homeowner’s solar panels to overheat the tank. Then, when hot water is called for, it mixes it with cold water to cool down to the appropriate temperature. That allows the water heater to make the most of excess solar production, essentially turning the tank into a battery that stores energy for a cloudy day.
In other instances, when both weather and water demand are consistent, Cala’s water heater can slow down the speed of the compressor, lengthening the time it takes to heat the tank for an efficiency bump. “In water heating, when you slow down the compressor, you increase the efficiency of heat transfer by about 30%.” Rigney said. “It’s a pretty significant impact.”
And if there are house guests coming? Cala included a boost mode that people can activate on the tank or in an app.
Today, water heaters in the U.S. are split almost evenly between natural gas and electric resistance, with oil, propane and heat pumps rounding things out. Water heating is responsible for around 20% of the typical American household’s energy usage, and heat pump water heaters slash that significantly while also cutting people’s dependence on natural gas.
Heat pump water heaters may only make up a few percent of the market, but they are rapidly growing in share, helped in part by incentives within the Inflation Reduction Act. And while they’re more expensive to install up-front, they’re cheaper in the long run because they’re more efficient to operate, leading to lower household carbon emissions.
Rigney said that Cala will be buying parts from various suppliers and assembling the final product in the U.S. (“This is not a product that ships well,” he said with a laugh.) The company’s first product, a 65 gallon model, will cost $2,850; it’s available to pre-order with delivery sometime early next year. That’s about $800 more than competitors, though Rigney said that lower utility bills should eliminate that difference over time.
To support the rollout, Cala exclusively told TechCrunch that it has raised a $5.6 million seed round led by the Clean Energy Venture Group and the Massachusetts Clean Energy Center with Burnt Island Ventures, CapeVista Capital, and Leap Forward Ventures participating. With so few heat pump water heaters sold to date, “this is a category that is truly nascent,” Rigney said. “We think there’s an opportunity here to redefine what people expect a water heater to do.”