Strom AuraHeat 9kW Single Phase Stored Combi Boiler - Electric Combi Boiler with 35L Integrated Stainless Steel Buffer Cylinder

Rather than feeding cold mains water directly to the heat exchanger, the AuraHeat stores water at up to 80°C in the 35L stainless steel tank, then mixes it with incoming cold mains water through a digital programmable blending valve before returning the blend to the heat exchanger for final temperature trim. The result is that the heat exchanger sees pre-warmed water instead of cold water, enabling it to sustain the flow rates associated with gas combis. The hotter the tank, the longer it can keep the blended supply above the target temperature — extending the effective hot water duration well beyond what the 35L volume alone would suggest.

The 35L tank can be operated in four ways to match how the household uses hot water. Always On keeps the tank heated continuously at the set temperature, ready for immediate use. Always Off leaves the tank unheated and allows the boiler to function as a standard instant electric combi. Boost Once heats the tank a single time in around 22 minutes, useful when a bath is anticipated. Timed On heats the tank at the same time each day, allowing the household to schedule heating around off-peak tariffs or daily routines.

Strom's heat exchanger distributes the heating load across multiple independent strands, transferring heat evenly across the whole surface. This eliminates the concentrated hotspots that cause limescale to bake onto single-element designs, and keeps the water circuit physically separated from the heating strands — reducing corrosion and allowing individual strand replacement rather than replacing the whole unit.

Because each strand can be switched independently, the boiler modulates output from as little as 1kW up to 9.5kW in fine steps to match the central heating demand at any given moment. This reduces short-cycling, maintains a steadier flow temperature, and avoids the step-change behaviour of single-element electric boilers, all without the need for a separate weather compensation controller.

The domestic hot water side of the cylinder is heated indirectly via an integrated coil, keeping the DHW circuit separated from the central heating water. This limits contact between the DHW and the coil surface, giving significantly better scale resistance than a direct-immersion arrangement — important in hard water areas where limescale build-up would otherwise shorten element life.

A built-in diverter valve automatically switches the heat exchanger's output from central heating to DHW as soon as an outlet opens, mirroring the priority logic of a gas combi boiler. Programmable parameters then let the installer or user set whether stored volume, instantaneous flow rate, or a balance of both takes precedence during draw-off — giving per-household tuning that a fixed factory setting cannot provide.

With no combustion, the AuraHeat produces zero local carbon monoxide and requires no flue terminal, soffit clearance, or terminal guard. This opens siting options unavailable to gas or oil boilers: internal cupboards, flats, and properties where cutting through an external wall for a flue is impractical or impossible.

The on-board touchscreen display replicates the layout that installers and homeowners already know from gas, oil, and LPG boilers, showing heating and hot water status, current temperature, and a weekly programme. Handover to the end user does not require retraining on an unfamiliar interface.