Welcome to TESS

After months of work with heating installers and manufacturers, the MCS is currently consulting on a Thermal Energy Storage System (TESS) design and installation standard.

This standard would initially apply to central heating TESS such as heat batteries. This is one of the technologies that the Department for Energy Security and Net Zero is exploring to make sure every UK home has a pathway towards low carbon heating. This includes the 15 - 20% of homes where heat pumps are too expensive or too disruptive to install.

Once the initial TESS standard is introduced, the standard could then evolve in future to cover other TESS such as decentralised systems (such as storage heaters) and standalone hot water storage. If the scope of the standard evolves to cover standalone hot water storage, there may be implications for heat pumps (which are currently designed with efficiency rather than flexibility in mind).

As chair of the MCS working group on TESS, I'm happy to answer any questions people might have.

Responses to the TESS consultation are welcome by 5pm on 12 March 2025. You can find the consultation here on the MCS website:

https://mcscertified.com/consultation-thermal-energy-storage-systems/