Millions of homes waste enormous amounts of energy through needlessly heating water heaters which they do not always need. PowerTank wants to change this by integrating three simple, existing pieces of technology, adding machine learning, and unleashing the energy storage potential of things we already own. Consider this: a 50 gallon hot water tank with water at 150°F stores about 11 kWh of energy. And they already exist in millions of homes across the country. On the other hand, battery energy storage remains a niche market, and with an installed cost of around $400/kWh. The team believes that PowerTank can provide energy storage at a price an order of magnitude less than existing batteries, and can achieve scale far faster than batteries because they leverage existing assets that are already in homes. This technology can be installed by a professional in a less than 30 minutes, and saves the customer money through lower energy use, lower energy bills (particularly when on time-of-use rates), and shared payments for the grid services that the PowerTank provides.