At Kiko, we back early, science-driven, high-impact companies and support them through their growth journey.
Mixergy is pioneering in intelligent hot water tanks that optimize energy consumption, integrate with heat pumps and solar, while also creating free energy storage for homes. Their technology isn’t just about efficiency—it’s about fundamentally reshaping how energy is managed in buildings.
First principles conviction
Built on world-leading research in Oxford University Dr Pete Armstrong and his team have innovated on both the hardware and software integration of the home energy system, utilising a core overlooked asset at the centre of all homes in the developed world: hot water. We got early conviction in both the core physical fundamentals and Pete’s ability to innovate at the frontier of this industry. We’ve carried that conviction through the growth of the company, with revenues doubling year on year repeatedly.
Water is an exceptional energy carrier—it has a specific heat capacity four times greater than alternative thermal storage materials, while also being three orders of magnitude cheaper. On top of that, every home in the Western world can access a tonne of it in minutes through the free supply chain of the tap.
As homes transition away from high-power gas heating, they face difficult choices: pay a premium for electricity, invest in ways to use electricity flexibly or adopt smarter ways to use low-power domestic renewables. Mixergy’s technology addresses the core of this problem, while also improving household comfort and convenience.
The company’s technology is certified as the best performing available on the UK market and has knocked competitors out of the water in third party test results that we have seen.
Step-Change in Heat Pump Performance through hardware and software
We can’t talk about all the technology Mixergy is developing with its partners (but trust us—the performance delta is newsworthy).
What we can talk about is Mixergy’s breakthrough in integrated heat pump technology for hot water tanks — which combine a unique heat pump topology to integrate with a hot water tank; software to optimise home energy performance, and performance optimising algorithms around weather forecasting and occupancy.
Traditional heat pump systems require bulky outdoor units and suffer from slow reheat times. For the 200 million European flat-dwellers, the only practical renewable heating options have been balcony solar or air-to-air heat pumps functioning as fan heaters.
Unlocking a new category of renewables
Mixergy has redefined this landscape by integrating heat pump technology directly into a hot water tank, creating a new renewable heating solution for properties that previously had no viable options. While others are developing hot water tank-integrated heat pumps, third-party testing confirms that Mixergy’s system is:
- The best-performing hot water solution on the market—with a COP of 3.4 (0.4-1 higher than competitors, depending on ambient temperature) and 10x faster heating than competitors, all with no external façade installations.
- So controllable that, in smaller (1-2 bed) highly insulated homes, it could be used to provide not just renewable hot water—but also renewable space heating. This can deliver renewable heat in flats without the need to install an outboard heat pump on the façade of the building, saving ~£650 on install costs and avoiding changes to the building’s exterior.
This innovation can unlock a new practical option for renewable heating. Mixergy are working to make space heating in flats and urban homes—one of the largest residential categories in Europe—viable for the first time.
This is just one of the frontiers they are pushing on. We’re exited to back Pete’s team in this round and look forwards to being able to share their further technical progress.
