Reservoir raises $8 million for a predictive heat pump water heater

Reservoir, a Massachusetts startup building a heat pump water heater that predicts household hot water demand, raised $8 million in a seed round led by Asymmetric Capital Partners with participation from Founder Collective and MCJ, TechCrunch reported on 12 August 2026. The money is intended to fund more installations around the Boston area, the company’s initial market. Reservoir was co-founded by Luke Winston-Almanzar, previously chief business officer at 3D-printing company Formlabs, with Gabriel Parisi-Amon and Jake Felser.

The unit spends its first month in a home gathering data on water use patterns to train a model, then runs the heat pump when demand and electricity prices are lowest. TechCrunch reported that the heat pump is nearly four times more efficient than an electric water heater and five times more efficient than a natural gas version. Water heating accounts for about 18% of a household’s total energy budget, a figure TechCrunch links to the U.S. Energy Information Administration’s Residential Energy Consumption Survey. The 2020 survey puts residential water heating at 1,737 trillion Btu against 9,481 trillion Btu of total site energy for all homes, or 18.3%.

What the heat pump water heater costs

Reservoir sells two versions with installation included. The “Max” model costs $6,500 and the base “Core” model costs $5,000. Massachusetts residents qualify for a $1,050 rebate, bringing the Core price to $3,950, which TechCrunch described as competitive with or cheaper than existing heat pump water heaters. Reservoir’s own pricing page lists the post-rebate Max price at $5,450 and shows rebates of $1,200 in New Hampshire and $1,150 in Maine, neither of which TechCrunch mentions. The company offers a 10-year warranty.

The grid angle, and what has not been demonstrated

Reservoir has installed about 100 devices so far and Winston-Almanzar told TechCrunch the company hopes to reach around 1,000 installed by the end of next year. At that scale, he said, “That’s when you start talking about a megawatt-scale in terms of capacity”, pointing at aggregation for utility demand response programmes. TechCrunch reported that the company could aggregate its fleet for demand response rather than that it does so today, and no utility partner, programme or measured load-shift figure is named. The company says it has shown it can relieve strain on the grid at neighbourhood level, a claim TechCrunch attributes to Winston-Almanzar without supporting data.

Savings figures differ by source. Winston-Almanzar told TechCrunch a Reservoir unit would save typical Boston homeowners up to $1,000 per year in energy costs. Reservoir’s own homepage states potential annual savings of up to $800 against other tank water heaters. Neither figure has been independently measured.

The hardware carries a second function. Reservoir added an ultrasonic flow sensor to detect plumbing leaks anywhere in the home and send the owner an alert through its app. The Max version adds a recirculation valve for instant hot water and a mixing valve intended to stop pipes freezing in cold snaps, and TechCrunch reported that its 50-gallon tank can deliver up to 150 gallons of hot water in “party mode”. Reservoir also started its own plumbing arm to control installation, with Winston-Almanzar telling TechCrunch the company built direct relationships because “in a lot of cases, distributors weren’t embracing the new technology”.

Flexible household loads are moving up the policy agenda in the same states Reservoir sells into, a shift covered in earlier Winss reporting on New Jersey’s virtual power plant and energy efficiency plan. For households weighing the upfront cost, the practical starting point remains measurement, as set out in energy auditing for homes.

Background

Heat pump water heaters move heat from surrounding air into a storage tank instead of generating heat directly, which is why their efficiency multiples exceed those of resistance elements and gas burners. Grid-interactive control of these units, shifting heating to off-peak hours while keeping a full tank at the times a household actually draws hot water, has been studied for years as a low-cost source of demand flexibility, since the tank itself acts as thermal storage. The commercial obstacle has been price and installation rather than physics: heat pump units cost more upfront than resistance or gas tanks, and installation depends on plumbers willing to fit unfamiliar equipment. Reservoir’s approach addresses both by bundling installation into the sticker price, running its own plumbing operation, and leaning on state rebates. Neither TechCrunch nor Reservoir states the company’s founding year, and Reservoir says its installations began in late 2025, which makes the 1,000-unit target the first real test of whether the model scales beyond Boston.

Sources: TechCrunch; Reservoir; U.S. Energy Information Administration, Residential Energy Consumption Survey 2020

Featured image: photo by Pavel Danilyuk on Pexels (free Pexels license).

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Figen Sekin

I specialize in sustainability education, curriculum co-creation, and early-stage project strategy. At WINSS, I craft articles on sustainability, transformative AI, and related topics. When I’m not writing, you’ll find me chasing the perfect sushi roll, exploring cities around the globe, or unwinding with my dog Puffy — the world’s most loyal sidekick.