A heat battery can feed a wet radiator circuit if the product and system are designed for space heating. Existing radiators do not automatically prove compatibility.
The short answer
Start with room-by-room heat loss, then check radiator output at the proposed flow and return temperatures. The store must deliver the resulting power for the required hours and recharge within the available window.
Radiator output changes with temperature
A radiator rated at a high boiler temperature gives less heat at a lower flow temperature. Larger radiators, different emitters or improved insulation may be needed.
Power and duration
A home losing 6 kW on a cold design day needs heat at roughly that rate while conditions persist. Storage capacity determines duration; the heat exchanger and pumps must also deliver the power.
Keep the hydraulic design visible
Ask how water flows through the store, pumps, valves and emitters. Confirm minimum flow, zoning behaviour, weather compensation and what happens when only one small zone calls for heat.
Existing pipework
Old microbore, sludge, unbalanced radiators or weak circulation can limit any replacement system. The survey should identify cleaning, flushing or pipe changes rather than hiding them in a contingency.
Design for the cold day
An average-day calculation can under-size storage. Ask how the system responds when the store depletes during a prolonged cold period and whether that response uses peak electricity.
Your next step
Require a room schedule showing heat loss, installed emitter output at the proposed temperature and any radiator change. Keep it with the quote.
Sources
Primary and independent references checked by our editorial team.
- Energy storage options explained — Energy Saving Trust Checked 10 Nov 2026