What is this?
When a storage heater fails to charge overnight, it will be cold or barely warm by morning. This is different from a heater that charges but loses heat too quickly. The problem lies in either the off-peak electricity supply, the heater's charging mechanism, or the Economy 7 meter switching times.
Common causes
- Economy 7 meter or timeswitch not activating off-peak supply
- Off-peak MCB tripped in the consumer unit
- Faulty boost relay or contactor in the consumer unit
- Heating element failed — heater cannot convert electricity to heat
- Input thermostat cutting out prematurely
- Wiring fault between consumer unit and heater
Is it dangerous?
A storage heater that is not charging is not dangerous. The issue is one of comfort and energy use rather than safety. However, if the heater's wiring or connections appear damaged or burnt, switch it off and call an electrician.
Can I fix it myself?
Turn the input dial to maximum to rule out a low setting. Check the consumer unit for a tripped MCB on the off-peak or heating circuit. If you have a boost switch for your storage heaters, try using it to see if the heater warms up — this confirms the heater itself works and the issue is with the off-peak supply.
When to call an electrician
Call an electrician if the boost switch works but overnight charging does not, if the off-peak MCB keeps tripping, if none of your storage heaters are charging, or if only one heater is failing to charge while others work.
What will an electrician do?
Test the off-peak supply timing and voltage
Check the Economy 7 meter switching operation
Inspect the boost relay or contactor for faults
Test each heating element for continuity
Check all wiring from the consumer unit to the heater
Repair or replace faulty components
Typical cost
£80 – £250
Off-peak supply issues may need the DNO or meter operator to fix the meter or timeswitch at no cost to you. Internal faults vary in cost.
