The ZEB: introducing the Zero Emission Boiler

The ZEB: introducing the Zero Emission Boiler

The ZEB® is a new concept in zero emissions heating in the home. Professional Builder’s Lee Jones talks to the developer of the technology.

When it comes to domestic CO2 emissions, a gas boiler is comfortably the biggest culprit and, with the imperative to cut carbon becoming all the more urgent, it is a reality that government, industry and homeowners will need to confront. Many of the recent pronouncements have focused on hydrogen’s potential as a replacement, with some leading manufacturers already trialing units powered by that gas, but one company is championing electrification as a solution.

An engineer by trade, when Johan du Plessis founded his company tepeo in 2018 he took up the cause of compact thermal storage as an alternative to oil and gas fired boilers. Johan, with his colleague and thermodynamics and energy systems expert, Chris Carver set about prototyping a system that would utilise a high-density thermal storage medium to efficiently capture and hold electricity in the form of thermal energy. That heat would then be released into a wet central heating system in order to power radiators and underfloor heating.

“After a number of iterations we had a working model that did exactly that,” explains Johan “and in the last few year we’ve been refining the concept, and now have a patent on some of the technologies involved. The result is the ZEB® (Zero Emission Boiler), a plug and play replacement for a gas, oil, LPG or direct electric boiler.” The unit is about the size of washing machine and connects into exactly the same pipes that a conventional system boiler would be plumbed into, requiring no change to an existing property’s heating infrastructure or an installer’s established practices. Instead of running from oil and gas, however, the ZEB is electrically powered, providing a genuine low carbon solution that could save up to 3 tonnes of CO2 from a typical home’s annual emissions.

The innovations don’t stop there, however, because the tepeo team is also exploiting the power of the Internet of Things. Through some cutting-edge connectivity there’s the potential to dramatically cut domestic fuel bills, as Johan reveals: “The wholesale cost of electricity actually fluctuates enormously during the course of a typical day, but that’s something we can turn to our advantage. Every ZEB is linked to tepeo’s IoT infrastructure, allowing our cloud platform to talk in real time to each individual unit. It can then determine the optimum moment in terms of price point that the boiler should be taking electricity from the grid or PV array on the roof, and then storing it as heat until it’s needed. The ZEB essentially operates like a battery, but instead of storying energy in a chemical form, which is expensive and includes components which are damaging to the environment, we’re making use of an inert, low cost and environmentally friendly system.”

At present, the current model, is designed to replace system boilers but there are plans for a version that would work in place of a combi. In trials the ZEB has replaced gas boilers up to 30kW output, with homeowners enjoying exactly the same heating experience as they did previously. Compare that to a heat pump installation, where it might be necessary to increase radiator sizes, and the advantages are clear. Indeed, a ZEB can achieve the same heat outputs as a gas-fired boiler and, in terms of power and storage capacity, would be suitable for anything up to what is classified as the median UK home – or one that uses around 12MW hours of gas a year.

Another added advantage is that the ZEB eliminates the need for a flue, whilst there’s greater flexibility as to its where it can installed. It doesn’t have to be placed in the same location as the gas boiler, for example, or against an outside wall, and tepeo engineers have been making using of the spaces under stairs to site the equipment, whilst other relatively redundant areas of a property could be put to use. In fact, for the tradesperson familiar with gas boilers, it is anticipated that the job of fitting will be a straightforward proposition.

“It’s early days for our own solution but the direction of travel in terms of policy is clearly towards low carbon solutions,” concludes Johan, “and that will demand incentives if the new technologies are to be adopted quickly enough to make a difference. Ultimately, when it comes to the future heating of our homes, it’s likely there will be a mix of different solutions, and electrification will certainly be among them.”

For further information the ZEB from tepeo visit

Related posts