Mixergy, an Oxford University spin-out specialising in smart water heating technology, has secured a £12 million funding round led by Barclays Climate Ventures to scale its grid-connected hot water solutions.
The investment, announced today, aims to transform home heating by reducing energy costs and enhancing renewable energy integration, addressing rising electricity prices and supporting the UK’s net-zero ambitions. With additional backing from Oxford Science Enterprises, Kiko Ventures, Nesta, and EDP Ventures, the capital injection brings Mixergy’s total funding to $34.8 million.
Mixergy’s technology promises to cut household hot water bills by up to 60% through its innovative, grid-connected water tanks, which optimise energy use and store surplus renewable power.
Founded in 2014 by Dr Pete Armstrong and Ren Kang, the company has pivoted from direct sales to a licensing and partnership model, targeting new builds, social housing retrofits, and commercial properties.
The funding will bolster research and development, enabling Mixergy to refine its hardware and software for energy utilities, property developers, and heating system manufacturers.
The UK energy market provides fertile ground for such innovation. Ofgem data show that, despite a recent 10% reduction in the energy price cap, household bills remain 60% higher than pre-2021 levels. Meanwhile, U.S. electricity prices have risen 5% above inflation since 2020, according to the Bureau of Labor Statistics. Mixergy’s solution arrives as governments and utilities grapple with decarbonisation and grid stability amid growing renewable energy adoption.
Mixergy’s tanks employ a top-down heating mechanism, warming only the water needed rather than an entire tank, which reduces energy waste by up to 40%. Integrated with machine-learning software via the Mixergy App, the system allows users to monitor and optimise consumption while storing cheap, renewable energy during off-peak periods.
This creates a distributed network of thermal batteries, easing grid pressure during peak demand—a critical feature as wind and solar power accounted for 35% of UK electricity in 2024, per National Grid statistics.
Pete Armstrong, Mixergy’s CEO, framed the technology as a win-win: “Why pay windfarms to shut down when we can pay households to switch on? This investment accelerates our ability to deliver scalable solutions, helping partners navigate a shifting energy landscape while improving grid resilience.” His comments nod to the £1 billion spent annually in the UK to curtail renewable generation when supply outstrips demand, a figure cited by energy consultancy Cornwall Insight.
British Gas, a key collaborator, has rolled out Mixergy eXtra, a tariff rewarding users for grid-supportive behaviour. Meanwhile, Mixergy’s heat pump-integrated cylinders have gained regulatory approval and feature in the UK government’s Home Energy Model, a framework for future housing standards.
