Now is the time for smart, secure hot water

1 June 2025

The Smart Secure Electricity Systems (SSES) framework offers an opportunity for manufacturers of smart appliances to deliver real savings for consumers, says Andrew Keating.

The UK’s Smart Secure Electricity Systems (SSES) framework is not just another policy initiative. It is a critical point in time for the energy sector. It marks a decisive shift toward a more flexible, responsive and digitally secure electricity grid. For manufacturers of heating technologies, particularly hot water systems, this presents both a challenge and a significant opportunity.

Let’s be clear: flexibility is no longer a future aspiration; it is an operational necessity. If we are serious about achieving net zero, then we must be equally serious about enabling the grid to respond dynamically to supply and demand in real time. That’s precisely what the SSES sets out to do, by requiring smart appliances, including hot water systems, to meet high standards for interoperability, cybersecurity and demand-side response.

Some voices in the industry have called for delay. They argue that the scope is too ambitious or that the timeline – currently around 20 months for initial compliance – is too short.  From our perspective at Mixergy, the real question isn’t whether the industry ‘can’ deliver.  It’s whether it ‘will’.

At Mixergy, we’ve already delivered. Our smart hot water cylinders meet the PAS 1878:2021 functional specifications for smart appliances and supports the demand-response best practices outlined in PAS 1879.  We’re already compliant with the tight cybersecurity controls of ETSI EN 303 645 and primed for the upcoming MCS Thermal Energy Storage System (TESS) standard on thermal storage tanks. Our cylinders can interact with demand-side response aggregators and shift with the grid in real time.  This is not theoretical. Our systems are installed and operating in homes across the UK today. The technology is working, and it is already delivering tangible benefits to both consumers and the system as a whole.

No time for delay

We didn’t wait for perfect alignment or further clarification. We recognised where policy and technology were heading and invested early in a platform that is designed from the ground up to comply with the standards that are now coming into force. Delaying now would not only lock in legacy technologies that can’t interact with the grid; it would actively undermine the early innovators who did the work to get ahead.

Let’s not forget what’s at stake. The UK is currently spending over a billion pounds annually to curtail wind generation, not because we lack renewable supply, but because we lack the flexibility to use it effectively. That is money wasted, clean energy lost, and progress slowed.

For manufacturers facing the SSES challenge, the scope of compliance is not trivial. These systems must handle time-of-use optimisation, respond to grid signals, maintain operation during connectivity failures, and meet rigorous cybersecurity protocols, such as ETSI EN 303 645. That’s in addition to the functional requirements around user override, fail-safe behaviour, and multi-supplier interoperability.  It is a major technical undertaking, and attempting to develop a proprietary platform from scratch is likely to involve high R&D costs, multi-year lead times and significant certification burdens.

Up to standard

That’s precisely why Mixergy’s licensable smart hot water platform offers such a compelling alternative. Our system is already aligned with PAS 1878 and PAS 1879, fully supports demand-side response, and meets the necessary IoT security standards. We’ve integrated with energy suppliers like Octopus Energy, provided frequency response services to the National Grid ESO and are the only manufacturer with a hot water system listed in SAP Appendix Q for additional energy savings, making a demonstrable impact on EPC scores for new builds.

Our technology has been proven in thousands of homes and trial programmes, delivering real savings to households by heating water when energy is cheapest or greenest. Through machine learning and dynamic tariff integration, we’re helping consumers get the most from their appliances, and helping the system by balancing demand intelligently.

OEMs can adopt this platform either as a full system or through our ‘Mixergy Light’ variant, which integrates into existing product lines. Either way, it enables manufacturers to meet SSES standards rapidly and confidently without derailing product roadmaps or incurring the overhead costs of developing and certifying a full cloud and control stack.

This isn’t just about compliance – it’s about staying competitive in a rapidly evolving energy market.  The government’s message is clear, and the policy framework is in place. The question now is not whether the smart future is coming.  It’s whether the industry is ready to embrace it or risk falling behind.