Cala Systems is a company with a clear mission: to decarbonize domestic hot water without anyone having to sacrifice on comfort or convenience.
To that end the company has poured its expertise and countless development hours not only into fluid and thermal physics, but also software engineering, the complexities of the electrical grid and energy markets, and even the psychology of human comfort.
Michael Rigney, company CEO and Co-Founder has 20 years of leadership experience in climate and energy start-ups combined with a background in building products and thermal sciences.
The evolution of energy markets and the electric grid to fight climate change has been a central theme in Rigneys work at utility enterprise software company EnergySavvy (now part of Uplight), grid infrastructure hardware company Gridco Systems, and demand response industry-leader EnerNOC.
Earlier in his career, he co-founded commercial trade credit company BlueTarp Financial, which served tens of thousands of professional contractors. Rigney holds an MBA from Stanford and a B. Eng from Dartmouth with a focus in heat transfer and fluid dynamics.
Rigney spoke with CONTRACTOR about what state-of-the-art means for heat pump water heating, and what the future might hold.
CONTRACTOR: The previous administration saw a big investment in heat pumps and heat pump technology, and now, with the current administration, were seeing the pendulum swing back, favoring more traditional methods of water heating. What do you think is the future of water heating in the US?
Michael Rigney.
Michael Rigney: Cala was founded before the IRA, and our business has never been dependent on federal policy.
Heat pump water heaters will play a significant role in the future of water heating in our view, tens of percentage points and ultimately more. This is really about cost, because approximately 45% of US homes rely on electric resistance water heaters, and in almost every state, they make up over 25% of the market. Another 6% of the US market uses oil and propane, which are also expensive fuels. Replacing these with heat pump water heaters offers immediate, measurable savingswithout needing to wait on policy or subsidies. To choose just one example, a family of four could see over $500 in annual operating cost savings with Cala versus an electric resistance water heater at the national average electricity price of $0.1745/kWh.
Related to this savings example, in the next year the average price residential retail electricity price increase is 6.7%.
More broadly, electrification isnt a trendits a trajectory. Heat pumps have outsold gas furnaces for three years running, and the desire to eliminate fossil fuels from the home continues to grow. Heat pump water heaters are a key part of that transition.
And lets not forget that state-level programs like Mass Save are stepping up where federal momentum may slow. Plus, the DOEs finalized efficiency standards have a no-rollback provisionso progress may bend, but it wont break.
In short, water heating is already largely electric and smart, connected systems like Calas are set to play an even bigger role in that future
CONTRACTOR: How does intelligent management work to get maximum efficiency out of what is an inherently highly efficient technology?
Rigney: Standard heat pump water heaters may use efficient technology, but theyre still operating on century-old logic: water gets cold, turn on heat. Thats where Cala is different. Our intelligent control system transforms a reactive product into a predictive one.
By pairing a variable-speed compressor with a built-in mixing valve, Cala doesnt just heat water efficientlyit optimizes across comfort, cost, carbon, and coordination with the rest of the home.
Say youve got a typical household where everyone showers in the morning. Most HPWHs would kick into high gearand even use electric resistance backupto reheat the tank right after. That hot water just sits there all day while the house is empty. Calas predictive control knows the usage patterns and can reheat more slowly, using less energy and operating the compressor at its most efficient speed.
Or if youve got rooftop solar, Cala can shift its heating window to take advantage of peak solar production, heating more quickly and to a higher temp when clean energy is abundant.
In short, the tech is already efficientbut its smart controls combined with the right data and hardware components unlocks its full potential.
CONTRACTOR: What do installing contractors need to know to help their customers make smart choices about their water heating systems, given all the variables at play?
Rigney: Contractors are on the front lines of one of the biggest transitions in home energyso the key is being able to translate a complex landscape into clear, confident guidance for your customers.
The biggest thing to understand is that water heating isnt one-size-fits-all anymore. Fuel type, household demand, utility rates, available incentives, solar integrationall of these play into what makes the right choice for a given home. Thats why product knowledge matters more than ever.
For example, many homes still rely on electric resistance water heaters, especially in retrofit situations. Replacing those with a heat pump water heater often offers immediate savings, and the payback can be fast. But not all HPWHs are built the same. Most still use basic, reactive controls. Calas system is predictiveit learns usage patterns, uses a variable-speed compressor for better efficiency, automatically adjusts tank setpoint, includes a built-in mixing valve and coordinates with solar or smart panels when available. That means efficient hot water is consistently available when needed a better experience for your customer.
And yesreliability matters. Weve heard the concerns about heat pump durability, and Calas predictive control helps reduce unnecessary cycling, which minimizes wear and extends the systems lifespan.
The more contractors understand these differences, the more they can position themselves as trusted advisorsoffering solutions that arent just code-compliant or rebate-eligible, but genuinely smarter for the home and the homeowner.
