A storage heater takes in electricity during scheduled charging periods, stores heat in an insulated core and releases it into a room later. For a London homeowner, landlord or business in the M25 area, a fault can mean a cold room, heat arriving at the wrong time or a heater that runs out of warmth before the evening. Some models rely mainly on stored heat; others also have fans, electronic controls or a separate direct-heating function. Finding the cause means checking both the heater and its electrical supply, rather than assuming that every loss of heat needs a replacement appliance.
How a storage heater gets and releases its heat
Inside a typical storage heater, electrical elements heat a dense core, often made from purpose-made bricks. Insulation slows the release of that heat. Older models commonly have an input control, which affects how much heat is stored, and an output control, which manages its release. Opening the output early in the day can leave less warmth available later. Modern controls may manage charging and room temperature automatically, so the correct settings depend on the particular heater.
The charging supply may be controlled through your meter and electricity tariff. Some heaters have one electrical supply, while others use separate supplies for storage charging and controls, a fan or supplementary heating. A lit display therefore does not necessarily mean the storage elements are receiving power. Equally, a cold heater outside its charging period does not prove that its circuit has failed.
In a flat, shop or office, note whether one heater is affected or several stopped charging together. One cold unit points towards a local supply or appliance fault, although testing is still needed. Several affected heaters may indicate a shared charging circuit, switching problem or a change to metering arrangements. Recent meter work, tariff changes and alterations to heating schedules are useful details to give the electrician.
- —Record the model details from an accessible label without removing a cover.
- —Note when the heater last charged and whether its display or fan still works.
- —Check whether other storage heaters have developed the same problem.
Storage heater faults and the symptoms you notice
A heater that remains completely cold may have lost its charging supply, developed a failed element or stopped heating because a thermostat or thermal cut-out has operated. Partial element failure can reduce heat storage without stopping it altogether. A heater that becomes warm but cannot maintain the room temperature may instead have unsuitable settings, a charging problem or insufficient capacity for the space. Changes to room use, draughts and longer opening hours can expose an existing capacity limitation.
Excessive heat, poor control over heat release or warmth disappearing unusually early can point to a thermostat, sensor, damper or control fault. On fan-assisted models, a failed fan or obstructed air path can prevent stored heat reaching the room properly. Unexpected clicking, scraping or rattling deserves investigation, particularly if it is new or accompanies reduced performance. Some switching and expansion sounds are normal, so describe what has changed rather than relying on the noise alone.
A tripping circuit breaker or RCD can indicate damaged wiring, insulation failure in an element or another electrical fault. Repeatedly resetting the protective device does not fix the cause. Discolouration at the wall switch, an unusually hot connection point or a burning smell can indicate overheating connections. Continuing to use a faulty heater may worsen damage to terminals and cables, increase the risk of electric shock or fire, or leave the property without dependable heating.
Safe checks and when to stop using the heater
If there is smoke, burning, sparking or water near electrics, switch off at the main switch only if safe to do so, keep clear and call an emergency electrician. Call 999 for a fire. Do not approach a wet consumer unit or reach past a smoking heater to operate a switch. If the power cut affects the whole street, call 105. Our 24/7 emergency electrician service covers London and the M25 area for electrical faults that need urgent attention.
When there are no danger signs, check the user instructions, visible control settings and heating schedule. Confirm that an accessible wall switch has not been turned off accidentally. Consider whether a holiday mode, low temperature setting or clock change explains the loss of heat. Check your tariff information for the charging arrangements rather than assuming that every off-peak supply operates at identical hours. Do not open meter equipment or attempt to override its switching.
Keep clothes, curtains and furniture away from the heater, following its specified clearances. Never cover it to dry washing. You can look for blocked external vents without inserting anything into them or removing panels. Do not bypass a thermal cut-out, tighten internal terminals or repeatedly reset a tripping circuit. Storage heaters can retain substantial heat after switching off, and some have more than one supply: a dark display or one switched-off isolator is not proof that the whole appliance is safe to work on.
How an electrician investigates and repairs the fault
Diagnosis starts with the symptoms, heater type and charging arrangement. An electrician identifies the relevant supplies, isolates them safely and proves the equipment is dead before opening electrical connections. They check the condition of the local switch, connections and circuit wiring, then investigate the components relevant to the fault. Depending on the model, these may include heating elements, thermostats, thermal cut-outs, sensors, a fan and electronic controls.
Testing helps separate a supply problem from an appliance failure. The electrician may check continuity, insulation resistance and protective conductor arrangements, using methods appropriate to the equipment and its electronics. For a fault that only occurs during scheduled charging, the switching arrangement also needs investigation. If the issue is within electricity metering or supplier-controlled equipment, the next step may involve your electricity supplier rather than an appliance repair.
A repair could involve replacing a suitable failed component or dealing with damaged wiring and connections. An operated thermal cut-out needs its cause investigated, not simply reset without checking for overheating or restricted airflow. Where electrical installation work is involved, BS 7671, the IET Wiring Regulations, is relevant to circuit suitability, protection, inspection and testing. The heater manufacturer's instructions also matter. Verification should reflect the actual repair, with any limitation on confirming a complete charging cycle explained.
Deciding whether to repair or replace a storage heater
Replacement may be appropriate when compatible parts are unavailable, internal damage is extensive or the heater no longer suits the room. A newer appliance still needs to match the available electrical supplies and intended tariff. Its controls, charging requirements, heat output and any supplementary heating supply should be considered together. Replacing a heater without investigating a faulty charging supply can leave the original problem unresolved.
Storage heaters are heavy, and safe removal may require controlled dismantling once the unit has cooled and been electrically isolated. Some older heaters may contain asbestos-containing components. The model and condition need checking before disturbing internal insulation; suspected asbestos requires appropriate specialist advice and handling. Do not break up an old heater or remove its core yourself to make it easier to carry.
For a replacement, the electrician checks circuit capacity, protective arrangements, isolation and the proposed location. The supporting surface, fixing requirements and clearances must also suit the new appliance. Any necessary changes to the fixed wiring should be assessed and tested as appropriate to BS 7671. Before using the replacement, make sure you understand its charging schedule, temperature settings and boost function, if fitted. In rented premises or business spaces, tell whoever manages the property about the fault and coordinate access without delaying action on an immediate hazard.
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Frequently asked questions
Why is my storage heater cold when its display is on?
The display and storage elements may use different supplies, so a working screen does not confirm that charging power is available. Settings, a missed charging period, failed elements or a control fault are other possibilities. Check the accessible settings and tariff information, but leave supply testing and internal checks to an electrician.
Should I reset the heater if it trips the electrics?
Do not keep resetting a breaker or RCD when the heater causes it to trip. The protective device may be responding to an insulation fault or damaged wiring. Stop using the affected heater and arrange electrical investigation. Never open the casing to reset an internal thermal cut-out yourself; the reason it operated needs checking.
Can I use the boost setting if overnight charging has failed?
Only use a boost function in accordance with the heater's instructions and when there are no signs of an electrical fault. It may provide direct heat using a separate supply, but it does not repair failed storage charging. If the heater trips, overheats, smells burnt or has damaged controls, stop using it rather than relying on boost.
Does a storage heater need to be cold before repair?
Stored heat can remain in the core long after the electrical supply is switched off. Internal work or dismantling may need to wait until the heater has cooled sufficiently. Tell the electrician when it last charged and whether it is still hot. Do not remove covers or try to speed cooling by interfering with its insulation.
Why do all my storage heaters stop charging together?
A shared charging supply, switching arrangement or metering issue may be responsible, especially after a tariff or meter change. Check whether ordinary lights and sockets still work, and note any recent changes. An electrician can investigate the installation; your electricity supplier may need to address metering. For a street-wide power cut, call 105.