From heat pumps and home batteries to electric appliances and solar panels, smart products are transforming how we build and retrofit our homes. The promise isn’t just about accelerating the energy transition—it’s about creating genuinely better products that people actually want to use.
At MCJ, we’re backing the startups defining this new generation of home technology: companies building products that make our homes cleaner, healthier, and more efficient. Our portfolio includes Quilt’s elegantly designed heat pumps and Base Power’s distributed battery and energy storage solutions—products that don’t ask homeowners to compromise on performance or experience.
Today, we’re excited to announce our investment in Reservoir.
Reservoir is reimagining the heat pump water heater from the ground up. Their system delivers up to 6x the efficiency of gas units while solving frustrations that homeowners didn’t even know were solvable.
The standout feature? No-Wait Shower—hot water delivered to your faucet before you even turn it on. By intelligently combining heat pump technology with recirculation, Reservoir eliminates the wasteful ritual of running water down the drain while waiting for heat. It’s the kind of luxury-meets-efficiency innovation that changes how people think about “smart home” technology.
Reservoir’s Home Protect system brings commercial-grade monitoring to residential applications, using ultrasonic flow sensing powerful enough to detect thermal expansion. It predicts freezing pipes, alerts you to leaks, and uses electronic corrosion control to extend tank life up to 20 years. And all of it is controllable from anywhere. This is home technology that doesn’t just perform better—it makes daily life noticeably better.
We’re excited to announce that MCJ participated in Reservoir’s $5 million Seed round, led by Founder Collective.
What is Reservoir?
Reservoir is the world’s smartest water heater, engineered to deliver efficiency without sacrifice. The system achieves up to 6x the efficiency of traditional gas tank heaters while introducing three core innovations that fundamentally improve the hot water experience.
Thermal Intelligence - Reservoir’s adaptive software ensures you get plenty of hot water without oversizing your system. By intelligently managing heating cycles and capacity, it delivers performance that makes traditional sizing calculations obsolete.
No-Wait Shower - The signature feature that makes Reservoir instantly recognizable: hot water at your faucet before you even turn it on. Reservoir is the only water heater smart enough to combine a heat pump with recirculation, eliminating the waste of running water down the drain while waiting for heat. It’s a luxury experience that also happens to be dramatically more efficient.
Home Protect - Commercial-grade protection designed for residential homes. Reservoir’s system includes:
Ultrasonic flow sensing so powerful it can detect the thermal expansion of water, catching leaks before they become disasters
Predictive monitoring that alerts freezing pipe danger
Active protection using built-in recirculation to heat hot water lines
Electronic corrosion control that extends tank life up to 20 years
All of this is manageable from anywhere through Reservoir’s app, giving residents as much or as little control over the home’s hot water system.
Reservoir works by managing four independent heating elements, including an ultra-efficient heat pump, to deliver abundant hot water with maximum efficiency. Unlike traditional heaters that simply fire on demand, Reservoir uses intelligence to decide when and how to store energy. In practice, it becomes a thermal battery that provides a foundation for future feature upgrades.
Why Did We Invest?
Compelling Founder-Market Fit
While Reservoir’s product sets a new standard for heat pump water heaters, we invested in their stellar team. Water heating accounts for 20% of home energy use, making it one of the highest-impact opportunities in residential decarbonization—and we couldn’t be more excited to back the founders reimagining it.
The company’s co-founders crossed paths via the MCJ network in the summer of 2023. Luke Winston was exploring his next adventure after scaling one of the most iconic 3D-printing companies in the world, and Gabe Parisi-Amon was looking to build his next startup in the electrification space after a long career as an Apple supply chain leader.
Reinventing a $100B+ home energy market requires an unusual combination: proven hardware scale-up experience, climate tech impact, and deep technical expertise. Reservoir’s leadership has all three.
Luke Winston (CEO) scaled Formlabs from an early-stage startup into a $2B global 3D printing leader with 1,000 employees, building out its 300-person sales and service organization along the way. He has deep experience taking novel hardware products from lab prototype to mass adoption. Luke holds degrees in Chemistry and Physics from Harvard, plus an MBA and MPP in Climate Policy from Harvard Business School and the Kennedy School.
Gabriel Parisi-Amon (CPO) co-founded Nebia (YC ’15), a water technology company that saved 1 billion gallons of water and 40 GWh of energy before its 2023 acquisition. He brings consumer product design expertise and a proven track record building climate hardware that customers love. Gabe holds a BS and MS in Mechanical Engineering from Stanford and an MBA from Harvard Business School.
Jake Felser (CTO) is a full-stack engineering leader who served as CTO at Freight Farms and VP at Eatsa, with expertise spanning mechanical, electrical, firmware, and software systems. He also built the San Francisco office for Cooper Perkins, giving him the cross-disciplinary depth to integrate advanced hydronics, heat pumps, and machine learning into one cohesive product. Jake holds a BS in Mechanical Engineering from Olin College.
Together, the team combines proven go-to-market execution, thoughtful consumer product design, and comprehensive technical expertise—everything needed to transform how Americans heat water in their homes.
A Wedge with Grid-Scale Potential
Reservoir is starting with domestic water heating—a $15B annual replacement market—but the technology unlocks something far more valuable. By integrating heat pumps, advanced hydronics, and machine learning, Reservoir transforms hot water from a utility into a distributed energy asset.
At scale, millions of Reservoir units can function as a virtual power plant, delivering tens of gigawatt-hours of storage capacity and gigawatts of flexible demand response—all while improving, not compromising, the customer experience. Water is one of nature’s most efficient energy storage mediums, and Reservoir is the first to truly harness that potential at the residential level.
The path forward is clear: start with the water heater, expand into whole-home heating and cooling, and build the distributed thermal energy infrastructure that modern homes need. Reservoir isn’t just making a better appliance—they’re creating an expandable platform at the intersection of hardware, software, and the grid.
And progress has been swift. The company recently achieved full certification and is ramping up production just one year after raising its Seed funding. Reservoir is launching first in the Boston area, and we’re excited to support them as they scale from single-home installations to grid-scale impact.