Mixergy

Mixergy is an Oxford University spinout that has developed a patented smart hot water cylinder that fundamentally rethinks how homes store and use energy. Founded in 2014 by Pete Armstrong and Ren Kang during their PhDs at Oxford's Department of Engineering Science, the company's tanks heat water from the top down — rather than heating the whole tank like a large kettle — meaning only the water needed is heated at any given time, reducing energy use by up to 40–60% and heating water up to five times faster than a conventional tank.

Each Mixergy cylinder is connected via an IoT platform that enables intelligent scheduling, real-time monitoring, and demand-side response participation. The tanks can absorb surplus renewable energy from solar or wind generation during off-peak periods and release it as needed, effectively acting as distributed flexible energy storage units within the national grid. This “Internet of Tanks” capability positions Mixergy as critical infrastructure for the UK's clean energy transition.

Mixergy has attracted backing from Foresight Williams Technology, IP Group, Oxford Sciences Enterprises, Barclays Climate Ventures, Nesta, and EDP Ventures, completing a £12 million round in 2024. Tanks are available nationally through British Gas and other installer networks, and the company is pivoting toward a technology licensing model for housing developers, social landlords, and commercial building operators.