Boston-based startup Reservoir has raised $8 million to turn conventional water tanks into smarter, cheaper and safer home appliances, the company said, using the seed funding to accelerate growth in Boston and expand into more U.S. cities.
According to the U.S. Energy Information Administration, a household water heater uses nearly a quarter of a home’s energy — a share that can be higher for frequent long showers. Reservoir’s pitch is to cut those bills while helping prevent leaks and other costly home repairs and promoting greater use of renewable power.
Reservoir launched in 2024 and began installing its predictive, heat pump water heaters in late 2025. To date, the company has installed systems in nearly 100 homes across the Boston metro area. The $8 million seed round, announced in early August, was led by Asymmetric Capital Partners with backing from Founder Collective and MCJ.
Smart water heaters: how the system works
Reservoir’s units add predictive controls to a traditional tank-style water heater. The system heats water ahead of anticipated demand and targets times when solar output is high or grid rates are low, storing ultra-hot water in the tank like a large battery for later use. The company also says the heater doubles as a safety system, guarding against issues such as leaks, frozen pipes, fumes and bacteria.
Reservoir reports that homeowners can save up to $800 a year on energy bills compared with conventional tanks. The company notes that water-related issues are significant for homeowners: the area of the home served by water heaters is linked to 24% of insurance claims for unexpected water damage.
Although its systems are pricier than conventional water heaters up front, Reservoir says that once installation costs and available incentives are applied the pricing is comparable. Many Massachusetts households can qualify for more than $1,050 in rebates and access 0% financing through state and regional programs. “We can offer more affordable pricing than traditional water heaters because we design, build, and install them ourselves,” said Luke Winston-Almanzar, Reservoir’s co-founder and CEO.
