Mixergy

Mixergy Ltd. is an Oxford-based company that develops smart hot water tanks designed to reduce energy consumption and support grid stability. Founded in 2014 as a spin-out from the University of Oxford's Department of Engineering Science by Pete Armstrong (CEO) and Ren Kang (Head of Operations and Research), the company originated from their PhD research into intelligent hot water systems. Their concept was to create a network of smart hot water cylinders that could function as a virtual power plant, storing surplus energy to provide flexibility to the national grid and facilitate the integration of renewable energy sources. The company's core product is a smart hot water cylinder that utilizes a technology called thermal stratification. Unlike conventional tanks that heat the entire volume of water from the bottom up, Mixergy's system heats only the required amount of water from the top down. This approach reduces energy waste and provides hot water more quickly. The tanks are equipped with sensors that allow users to monitor the exact amount of available hot water via a mobile app, which also enables scheduling, temperature control, and cost tracking. The system's machine learning capabilities can optimize heating schedules based on off-peak electricity tariffs, which can save users up to 40% on hot water bills. Mixergy's business model encompasses a technology licensing and strategic partnership approach, targeting new build developments, social housing retrofits, and commercial properties. The company collaborates with utilities, such as a partnership with British Gas for the 'Mixergy eXtra' offer, which provides financial incentives to homeowners who connect their smart cylinders to the grid. The tanks are designed to be compatible with various energy sources, including gas boilers, solar PV panels, and heat pumps, making them a versatile solution for the transition to electric heating. By connecting a fleet of these tanks, Mixergy creates a decentralized energy storage network that can absorb excess power during periods of high renewable generation and reduce demand during peak times. Since its inception, Mixergy has raised approximately $37.9 million over eight funding rounds from investors including Barclays Climate Ventures, EDP Ventures, Nesta, Oxford Science Enterprises, Kiko Ventures, Foresight WAE Technology, and Centrica. The company has received multiple accolades, including the King's Award for Enterprise in Innovation in 2025, one of the highest honors for a UK business. Keywords: smart hot water tanks, thermal stratification, energy efficiency, grid flexibility, demand side response, cleantech, University of Oxford spin-out, IoT, home energy management, renewable energy integration, virtual power plant, smart heat battery, energy storage, heat pump compatible, solar PV integration, residential heat storage, decarbonisation, energy savings, smart grid technology, Pete Armstrong, Ren Kang