New standards mark an important step towards giving installers, customers and funders greater confidence in heat battery boilers
tepeo has welcomed MCS’s announcement that it will launch a pilot for new Thermal Energy Storage Systems (TESS) standards, describing the move as an important step towards bringing heat battery boilers into the mainstream of UK low-carbon heating.
MCS has revealed plans to pilot a Thermal Energy Storage Systems Design and Installation Standard, known as MIS 3008, and a Pre-Sale Information and System Performance Estimate Standard, known as MCS 038.
Thermal Energy Storage Systems, including heat batteries, are emerging as an important technology in the UK’s transition to net zero. They can store energy as heat and release it later, helping homes make better use of cheaper, typically off-peak, electricity.
For tepeo, the announcement is a significant milestone for the heat battery boiler category.
tepeo’s ZEB is a smart heat battery boiler designed to replace fossil fuel boilers and expensive direct electric heating in suitable homes. It works with familiar wet central heating systems, including radiators and hot water, while storing energy as heat in a highly insulated core.
In simple terms: it charges like a battery and heats like a boiler.
A clearer framework for a growing technology
The new MCS pilot introduces Thermal Energy Storage Systems into the MCS Scheme, following growing interest from government and industry in the role heat batteries could play in decarbonising homes.
MCS has brought together a technical working group on Thermal Energy Storage, chaired by Tom Lowe, Founding Director of Thermal Storage UK. The group includes volunteer experts from across the sector, including installers, manufacturers, trade bodies and consumer champions.
Over the past nine months, the working group has developed two proposed standards:
MIS 3008: Thermal Energy Storage Systems Design and Installation Standard
This outlines the requirements for the design and installation of thermal energy storage systems.
MCS 038: Pre-Sale Information and System Performance Estimate Standard
This describes the methodology for estimating the minimum storage capacity of a TESS to meet a home’s heating demand on the coldest days of the year.
Together, these standards are designed to support high-quality installations, improve consistency across the market, and help consumers understand what to expect before a system is installed.
Why this matters for installers
For heating engineers and installers, tepeo says the MCS pilot could provide a clearer route into a fast-growing area of low-carbon heating.
Heat pumps will play a major role in decarbonising UK homes, but no single technology will be right for every property. Heat battery boilers offer another option, particularly for households looking for a familiar, low-disruption replacement for a boiler.
The new standards could help installers by providing:
- Clearer guidance on system design and installation.
- A consistent approach to performance estimates.
- Greater confidence when advising customers.
- A route towards MCS certification for TESS installations.
- A stronger framework for building skills in smart electric heating.
“Heating engineers are central to the UK’s energy transition. These new MCS standards mean they’ll have the clarity and confidence to offer customers the very latest in thermal storage – and grow their businesses while doing it. At tepeo, we hope to make that journey as straightforward as possible.” – Adam Litchfield, tepeo
Building customer confidence
MCS says the creation of dedicated standards for Thermal Energy Storage Systems will give consumers confidence that every system is designed and installed to a trusted, industry-recognised benchmark.
tepeo believes this is critical for bringing heat battery boilers into the mainstream.
For homeowners, the benefit is simple: more confidence when choosing a low-carbon heating system.
For installers, it means less guesswork and a clearer framework for delivering high-quality systems.
For funders and housing providers, it helps create the consistency needed to support wider deployment of low-carbon heating technologies.
Installer perspective
Leaping Hare Renewables, a Norfolk-based installer, said:
“Thermal storage has always had huge potential, and the MCS TESS standard finally gives us a clear framework to deliver it. As installers, we now have the confidence to offer high-quality, compliant systems that support the UK’s transition to net zero.”
Policy and funding momentum
The MCS pilot comes as heat batteries gain wider recognition in policy and funding discussions.
Heat batteries are already included in the government’s Warm Homes: Social Housing Fund, which supports the decarbonisation of social housing. The recent Boiler Upgrade Scheme consultation also considered broadening the scope of eligible technologies, with heat batteries identified as a possible addition.
MCS has said the development of these standards, and the eventual inclusion of TESS in its certification scheme, will help ensure consumers and other stakeholders can have confidence in the quality of TESS installations.
tepeo says this matters because heat batteries have the potential to widen the choice of low-carbon electric heating solutions available to households and small businesses, particularly where other options may not be suitable.
Entering the pilot phase
The new TESS Installation Standard and System Performance Estimate Standard will now enter a pilot phase with selected Certification Bodies and volunteer installers.
The pilot will test the standards in real-world conditions, helping to ensure the requirements are clear, practical and deliverable for installers.
MCS will gather feedback from across the industry during the pilot, using this to refine the detail, build confidence in the technology and ensure the final standard supports both quality installations and consumer protection.
The process is expected to take several months to allow for thorough testing.
Once the pilot has concluded, the TESS standard will be finalised, allowing Thermal Energy Storage Systems to be introduced as an MCS-recognised technology.
Supporting installers with training and tools
tepeo is preparing to support installers as the market develops, with practical resources designed to help heating engineers understand, specify and install the ZEB heat battery boiler.
This includes:
- Training and onboarding.
- Technical guidance and specification materials.
- Support with the new MCS requirements.
- Performance and suitability tools.
- Product support for the ZEB.
- Installer-friendly design focused on reducing disruption on site.
The ZEB has been designed as a practical replacement for boilers in suitable homes, helping installers offer customers another route away from fossil fuel heating.
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A broader choice for low-carbon heating
tepeo believes the MCS pilot is an important step in helping the UK build a more flexible, practical and trusted low-carbon heating market.
Installers who step into this space early will be the ones customers turn to – not just for heat pumps or boilers, but for the smart, flexible systems that will let customers take advantage of the cheapest and greenest times to use energy.
Ready to get started? Get in touch to register your interest and access tepeo’s training and support for installers.
About MCS
MCS is the UK’s standards organisation for small-scale renewable and low-carbon technologies. Its certification schemes are designed to give consumers, installers and the wider industry confidence in the quality and performance of certified products and installations.