ONYX high-heat retention heater: smart efficiency for modern installations

The ONYX high-heat retention storage heater represents a major step forward in electric heating, bringing installers a solution designed for greater efficiency, simpler integration and real, measurable performance benefits.

At the core of ONYX is its exceptional heat retention. While traditional storage heaters lose stored heat rapidly, ONYX holds warmth for up to 16 hours, reducing reliance on boost heating and significantly lowering overall consumption. This consistent thermal output translates into long-term energy savings, higher comfort and fewer complaints – a combination that installers can rely on.

Where ONYX truly becomes a strategic choice is in its impact on EPC ratings. As EPC performance becomes central to property value, rental eligibility and compliance with upcoming low-carbon heating requirements, ONYX offers one of the most effective upgrade paths available. By charging during off-peak hours and releasing heat gradually, it reduces primary energy demand and naturally supports higher SAP scores. Its integrated smart controls – accurate thermostats, scheduling and open-window detection – reinforce EPC-friendly efficiency without requiring disruptive upgrades. For many homes, ONYX can help lift ratings from E to C or even B, supporting targets associated with Part L and the UK’s 2050 net zero ambitions.

A major innovation in ONYX is its Smart Charging capability. Instead of charging for the entire off-peak window, the heater uses an advanced algorithm to determine exactly how much stored heat will be needed the next day – and precisely when it should begin charging to reach that level on time. Because no storage heater can hold heat perfectly, ONYX prevents unnecessary energy loss by avoiding early charging. The result: it never charges more than needed, never earlier than necessary, avoids costly daytime top-offs, and always works to minimise heat loss – improving overall efficiency automatically.

Connectivity further elevates ONYX above other options. With WiFi Direct, installers no longer need external gateways or hubs. Once connected, users gain full access through the Rointe NEXA app – including schedules, real-time adjustments, consumption tracking, AI-based routines and geolocation-driven automation.

For installers and property owners, ONYX combines high retention, EPC-friendly performance, Smart Charging and seamless connectivity to set a new benchmark in modern electric storage heating – efficient, intelligent and ready for the future.

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