Storage heaters on Economy 7: how they work and how to cut the cost
By Dale @ ukaircontracker · facts checked
Quick answer
Storage heaters charge up overnight on Economy 7's cheaper night rate, storing heat in clay or ceramic bricks, then release it through the next day. A full seven-hour charge on a 2.55 kW heater uses up to 17.8 kWh; charge control usually stops it sooner. Set the input dial for tomorrow's weather and keep the output low until you need heat, so the heater does not run out by evening.
| Heater input rating | Full 7-hour charge (maximum) |
|---|---|
| 1.7 kW | 11.9 kWh |
| 2.55 kW | 17.8 kWh |
| 3.4 kW | 23.8 kWh |
Multiply by the off-peak (night) rate on your bill. Off-peak rates vary by supplier and region, so check your own tariff.
Using the dials
- Input (charge): how much heat is stored overnight. Turn it up the night before a cold day, down in mild weather.
- Output (boost or damper): how fast the stored heat escapes. Keep it low in the morning and turn it up in the late afternoon, when the heat is most needed.
- The convector or boost heater on some models runs at the day rate. Use it sparingly.
Is Economy 7 still worth it?
Economy 7 has a cheaper night rate and a dearer day rate. It pays when a large share of your electricity, such as storage heaters and an immersion heater, is used at night. If most of your use is in the daytime, a single-rate tariff can be cheaper. Compare using your own meter readings.
The RTS meter switch-off
Many older storage heater homes have a Radio Teleswitch (RTS) meter that switches between day and night rates. The RTS signal is being switched off in phases. If you have one, your supplier should contact you to replace it, usually with a smart meter that keeps an off-peak tariff.
Common questions
- How many hours is Economy 7?
- Seven hours of cheaper electricity, usually overnight. The exact times depend on your meter and supplier and are shown on your bill.
- Why do my storage heaters run out of heat in the evening?
- Usually the output dial is set too high in the morning, letting the heat out early, or the input is too low for the weather. Lower the output until mid-afternoon.
- Should I leave storage heaters on all the time?
- Leave them switched on at the wall so they can charge overnight, and control them with the input and output dials. Switching off at the wall in mild weather stops charging altogether.
- How much does a storage heater cost to install?
- The Energy Saving Trust puts typical installed costs at £900–£1,400 per room for electric storage heaters.