Storage Heaters: How They Work, Costs & Economy 7
Electric storage heaters charge overnight on off-peak electricity and release heat during the day. Common in flats and homes without gas.
Storage Heaters vs Other Heating: Quick Comparison
| Feature | Storage Heaters | Electric Radiators | Gas Central Heating |
|---|---|---|---|
| Annual running cost | £900–£1,400 3-bed home, Economy 7 | £1,500–£2,200 Standard rate electricity | £720 Cheapest option |
| Installation cost | £300–£500 per heater £1,800–£3,000 whole-house | £150–£350 per radiator | £2,500–£4,000 New gas boiler + radiators |
| Electricity tariff | Economy 7 required 9p/kWh off-peak, 28p/kWh peak (2026 typical) | Standard tariff 24p/kWh | N/A (gas 6p/kWh) |
| Control / flexibility | Low Charge overnight, heat all day | High Instant on/off, room-by-room | High Thermostat, timer, zones |
| Heat output control | Limited Modern models have fans + thermostats | Precise Digital thermostats | Precise TRVs on each radiator |
| Best for | Flats, homes without gas, predictable heating needs, Economy 7 tariff users | Supplemental heating, homes with heat pumps, properties without gas | Most UK homes with gas connection |
How Storage Heaters Work
Storage heaters contain ceramic bricks (or sometimes clay blocks) with high heat capacity. Electric heating elements embedded in the bricks heat them overnight during off-peak hours. The stored heat is then released gradually during the day.
Old storage heaters (pre-2010) release heat passively through convection and radiation. You cannot stop the heat once charged. Modern high-heat-retention storage heaters (sold since ~2010) have better insulation, programmable timers, and fan-assisted heat release, giving you more control over when heat is delivered.
Economy 7 Tariffs
Storage heaters are designed to work with Economy 7 tariffs, which offer cheaper electricity for 7 hours overnight (typically 00:30–07:30, though times vary by supplier). The heaters charge during this window.
- Off-peak rate (00:30–07:30)
- ~9p/kWh (2026 typical)
- Peak rate (rest of day)
- ~28p/kWh (higher than standard 24p/kWh rate)
- Meter requirement
- Dual-rate meter (separate registers for peak/off-peak usage)
The off-peak rate is cheaper than gas (6p/kWh), but the peak rate is expensive. If you use significant daytime electricity (e.g. working from home, electric cooking), the higher peak rate can offset the storage heater savings.
Running Costs
A typical 3-bedroom home with storage heaters uses 12,000 kWh/year for heating. On an Economy 7 tariff, assuming 80% of heating electricity is consumed off-peak:
- Storage heater annual cost
- £900–£1,400/year (Economy 7, 3-bed home)
- Gas boiler annual cost (same home)
- £720/year (gas at 6p/kWh, 90% efficiency)
- Electric radiators (standard tariff)
- £1,500–£2,200/year (electricity at 24p/kWh)
Storage heaters cost £180–£680 more per year to run than gas central heating, but less than half the cost of standard-rate electric radiators. The economics depend on your tariff and usage patterns.
Modern vs Old Storage Heaters
Old storage heaters (pre-2010):
- Poor insulation (heat leaks out overnight, wasted)
- No output control (all heat released whether you need it or not)
- Input dial sets overnight charge amount (manual guesswork based on weather forecast)
- Output dial adjusts damper (limited effect)
Modern high-heat-retention storage heaters (2010+):
- Better insulation (20–30% more efficient)
- Programmable timers (set heating schedules for different days)
- Built-in thermostats (stop charging when room reaches target temperature)
- Fan-assisted heat release (deliver heat on demand, not just passively)
- Some models can charge during the day if needed (adaptive charging)
Replacing old storage heaters with modern high-retention models can cut running costs by £150–£300/year for a 3-bedroom home.
Are Storage Heaters Right for You?
Storage heaters make sense if:
- You have no gas connection (common in flats, rural areas)
- You're already on an Economy 7 tariff
- Your heating needs are predictable (occupied during the day, empty at night)
- You want lower upfront costs than a heat pump (£7,000–£14,000)
- You're in a well-insulated property (EPC C or better) where heat demand is modest
Consider alternatives if:
- You have a gas connection available (gas central heating is cheaper to run)
- You need flexible on-demand heating (electric radiators or infrared panels)
- You can afford a heat pump (lower running costs, government grant available)
- You use a lot of daytime electricity (peak rate on Economy 7 makes it uneconomical)
Installation and Replacement
Modern storage heaters cost £300–£500 per unit including installation. A 3-bedroom home typically needs 4–6 heaters (living room, bedrooms, hallway), total cost £1,800–£3,000.
Installation requires a dedicated circuit from your consumer unit to each heater. An electrician will check your wiring is suitable (old wiring may need upgrading). The heater mounts on the wall (not freestanding) and must be positioned clear of furniture and curtains.
You'll also need an Economy 7 meter if you don't already have one. Your energy supplier can arrange this (sometimes free, sometimes £50–£150 installation charge).
Related Guides
- How Do Storage Heaters Work? Explainer + Diagrams
- Are Storage Heaters Expensive to Run? Cost Breakdown
- Electric Heating Systems: Types & Costs
- Heat Pump vs Gas Boiler Comparison
Sources
- Energy Saving Trust, "Electric Heating" guidance (storage heater performance data, 2026).
- Ofgem, "Economy 7 and Economy 10" tariff structure (off-peak hours and rates, 2026).
- Which?, "Storage Heaters Explained" (cost comparison data, 2025–2026).
- EST, "Measurement of Domestic Hot Water Consumption in Dwellings" (12,000 kWh/year typical heat demand, 2022).
- Electric Heating Company, "High Heat Retention Storage Heaters" product specifications (efficiency improvements, 2024).
- BEAMA (trade association), "Guide to Electric Storage Heating" (installation standards, 2023).
- Octopus Energy, "Economy 7" tariff rates (9p/kWh off-peak, 28p/kWh peak, June 2026).
Last reviewed: 2026-06-27