What is the difference between a modern storage heater and an old one?

Old storage heaters from the 1970s–1990s use simple clay or chamotte bricks, manual input charge dials (set by hand each evening), manual output controls (a damper that releases heat), and basic thermal insulation. They leak heat during the day regardless of demand and often run out of stored heat by early evening. Modern storage heaters such as the Dimplex Quantum and Elnur Ecombi use high-density ceramic bricks, enhanced polypropylene-encased mineral wool insulation, electronic automatic charge control (assesses previous day temperature history), and precise room thermostat control. They retain heat more effectively and deliver it more intelligently, reducing electricity consumption by 20–30% compared to old models.

Do storage heaters need to be on their own circuit?

Yes. Current wiring regulations and good practice require each storage heater to be supplied by its own dedicated radial circuit from the consumer unit. This is because storage heaters draw high charging current (a 1.7 kW heater on a 10 A circuit is fine, but a 3.4 kW heater requires a 16 A circuit). Running multiple heaters on a shared circuit creates overload risk during the charging period. Each circuit should have its own MCB of the appropriate rating and an RCD protecting it.

What is Economy 7 wiring and how does it work?

Economy 7 is a dual-rate electricity tariff where a cheaper rate applies for 7 hours overnight (typically 23:00–06:00 or 00:30–07:30 GMT, varying by region and supplier). Properties on Economy 7 have a dual-rate (two-rate) meter with a time switch that activates the off-peak supply during cheap hours. Storage heaters are wired to the off-peak terminals of the meter so they only charge during cheap-rate hours. Standard lighting and socket circuits remain on the standard rate. Economy 10 works similarly but provides 10 off-peak hours split across night, afternoon, and evening periods.

Can I replace old storage heaters myself?

Replacing a storage heater and connecting it to an existing dedicated circuit is notifiable work under Part P of the Building Regulations in England and Wales. It must be carried out by a competent person registered with a scheme such as NICEIC or NAPIT, or self-certified by a competent DIYer who notifies the local building control authority. In practice, the weight of storage heaters (up to 100 kg for large models) and the electrical connection requirements mean professional installation is strongly recommended. Attempting to connect storage heaters to non-dedicated circuits or ring mains creates a serious fire risk.

What size MCB do I need for a storage heater?

MCB sizing depends on the heater's rated input power: a 1.7 kW heater (7.4 A at 230V) needs a 10 A MCB; a 2.5 kW heater (10.9 A) needs a 13 A or 16 A MCB; a 3.4 kW heater (14.8 A) needs a 16 A MCB. All storage heater circuits must be RCD-protected. Use a Type B MCB — storage heaters have resistive loads without high inrush current, so Type B is appropriate and correct.

How much does it cost to run storage heaters?

Running costs depend on the Economy 7 off-peak rate and the heater's efficiency. A modern 2.5 kW Dimplex Quantum charged for 7 hours on Economy 7 at 13p/kWh uses 17.5 kWh overnight costing approximately £2.28. A typical 4-bedroom house with 5 heaters might spend £300–£550 per month in winter on heating — similar to gas central heating at current gas prices for an older uninsulated house, but potentially more expensive in a well-insulated home. Modern storage heaters on a competitive Economy 7 tariff in a well-insulated property can be competitive with gas.

Can I use storage heaters with a smart meter?

Yes. SMETS2 smart meters can manage dual-rate (Economy 7/10) metering electronically without a mechanical time switch. The smart meter applies the off-peak rate during programmed periods and communicates this to the energy supplier for billing. The storage heaters must still be wired to the off-peak supply terminal as before. Some suppliers are launching smart tariffs compatible with modern storage heaters that communicate directly with the heater's charge controller via Wi-Fi for optimised charging based on real-time grid conditions.

HEATING INSTALLATION GUIDE

Electric Storage Heater Installation UK: Modern Storage Heaters

A complete guide to electric storage heater installation in the UK — modern models versus old, Dimplex Quantum and Elnur Ecombi, dedicated circuit requirements, Economy 7 and Economy 10 dual-rate wiring, thermostat and charge control connections, and 2025 replacement costs.

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11 min readUpdated 2026-05-18Andrew Moore, Founder of Elec-Mate

Written and reviewed by Andrew Moore, founder of Elec-Mate, against BS 7671:2018+A4:2026, IET Guidance Note 3 and the IET On-Site Guide.

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Key Takeaways

1Modern electric storage heaters (Dimplex Quantum, Elnur Ecombi) are significantly more efficient than older models, using a combination of high-density ceramic bricks, enhanced insulation, and electronic charge and output control to reduce electricity consumption by 20–30%.
2Each storage heater requires a dedicated radial circuit with an appropriate MCB — typically 16 A or 20 A — because the high charging current (2–3.4 kW per heater) would overload a shared ring circuit if multiple heaters charged simultaneously.
3Economy 7 and Economy 10 tariffs supply two rates on a dual-rate meter: a cheap overnight rate (approximately 10–17p/kWh) during 7 or 10 hours of off-peak periods, and a higher standard rate during peak hours. Storage heaters must be wired to the off-peak supply only.
4Modern storage heaters use a separate room thermostat and an electronic charge controller to adjust heat input each night based on room temperature history and user-set comfort levels, eliminating the manual input charge dial of older models.
5Replacement costs in 2025 are typically £300–£700 per heater for the unit, plus £200–£450 per heater for installation (dedicated circuit, connection, testing). Whole-house replacements of 4–6 heaters cost £2,500–£5,500 installed.
6Storage heaters work best in properties where occupants are at home during the day to benefit from stored heat, where electricity is purchased on Economy 7 or Economy 10, and where alternative heating systems (gas, heat pump) are not viable.

01 · Heating Installation Guide

Modern vs Old Storage Heaters

Storage heaters store heat generated by cheap overnight electricity in ceramic or brick cores, releasing it through the day. The technology has existed since the 1960s, but modern models are dramatically more efficient and convenient than their predecessors.

Old models (pre-2000) — manual input charge dial (estimated by the user each evening), simple damper output control, poor insulation, consistent heat leakage through the day. Often too hot in the morning and cold by early evening. Heavy (up to 180 kg for large models). No room thermostat capability.
Modern models (2010+) — electronic automatic charge control using historical room temperature data to predict overnight charge requirement. High-density ceramic brick cores with superior mineral wool insulation. Room thermostat input for precise comfort control. App control and voice assistant integration on premium models. 20–30% reduction in electricity consumption versus equivalent old model.

The Government's ECO4 scheme and the Great British Insulation Scheme can fund storage heater replacement for eligible households in homes with an EPC rating of D, E, F, or G. An MCS-accredited installer is typically required for funded installations.

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02 · Heating Installation Guide

Popular Models: Dimplex Quantum and Elnur Ecombi

Two brands dominate the modern UK storage heater replacement market: Dimplex and Elnur. Both offer a range of outputs suitable for different room sizes and installation scenarios.

Dimplex Quantum — the UK market leader for modern storage heaters. Available in 1.5 kW to 3.4 kW input ratings. Features automatic charge control, room thermostat input, open window detection, and app control via the Dimplex Link hub. Uses a unique double-door damper system for improved heat retention. Compatible with Economy 7, Economy 10, and newer smart tariffs.
Elnur Ecombi — the primary competitor to Dimplex Quantum. Available in 1.0 kW to 2.5 kW output ratings. Features a built-in room thermostat, automatic charge control, and optional app control via a Wi-Fi interface. Well-regarded for build quality and competitive trade pricing. Particularly popular for social housing and ECO scheme installations.
Heatstore (Glen Dimplex) — a lower-cost option for budget storage heater replacements where the premium features of Quantum are not required. Suitable for landlord and student accommodation where simplicity and durability are the priority.

03 · Heating Installation Guide

Dedicated Circuit Requirements

Every storage heater must be supplied by its own dedicated radial circuit from the consumer unit. This is a regulatory requirement and a practical necessity given the high charging currents involved.

Circuit cable — 2.5 mm² twin-and-earth (6242Y) is appropriate for storage heaters up to 3.4 kW on a radial circuit with appropriate installation method. Confirm volt drop is within limits specified in BS 7671 Appendix 4 for the cable run length.
MCB rating — 10 A for heaters up to 2.0 kW; 16 A for heaters 2.0–3.4 kW. Type B MCB is correct for resistive storage heater loads. Each circuit must be protected by a 30 mA RCD in accordance with Regulation 411.3.3 of BS 7671.
Consumer unit capacity — a whole-house storage heater replacement involving 4–6 heaters may require a new or upgraded consumer unit with sufficient spare ways for both peak and off-peak circuits. An RCBO-equipped consumer unit simplifies individual circuit protection.
Local isolation — each storage heater should have a local means of isolation (double-pole isolator or appropriate switched fused connection unit) adjacent to the heater for safe maintenance access.

04 · Heating Installation Guide

Economy 7 and Economy 10 Wiring

Storage heaters only make economic sense when connected to a dual-rate (Economy 7 or Economy 10) tariff that provides cheap overnight electricity. The wiring arrangement differs from standard domestic circuits.

Dual-rate meter — the property must have a dual-rate electricity meter (or SMETS2 smart meter configured for Economy 7/10). The meter has two sets of terminals: one for the standard rate supply (peaks hours) and one for the off-peak supply. Storage heater circuits connect to the off-peak terminals only.
Time switch (old meters) — older Economy 7 meters use a mechanical or electronic time switch to switch the off-peak supply on during cheap hours. The time switch must be correctly set and periodically adjusted for GMT/BST changeover. Modern SMETS2 meters handle this automatically.
Off-peak consumer unit — storage heater circuits may be in a separate consumer unit (often labelled "off-peak" or "storage heaters") fed from the off-peak meter terminals, or in a split consumer unit with separate off-peak and peak busbars. The configuration varies by property age.
Hot water immersion — Economy 7/10 properties often also have an immersion heater on the off-peak supply. This is wired in the same way as storage heaters — dedicated circuit, off-peak meter terminal. Modern smart immersion controllers (Eddi, Mixergy) can also divert solar surplus to the immersion.

05 · Heating Installation Guide

Thermostat and Charge Control Wiring

Modern storage heaters require correct connection of both the power supply and the control wiring for the automatic charge control and room thermostat functions to operate correctly.

Dimplex Quantum wiring — the Quantum requires a three-wire connection: live (L) and neutral (N) from the off-peak supply for the heating element, plus a permanent live (PL) from the peak supply for the electronic controller. Without the permanent live, the controller cannot operate the room thermostat function or communicate with the Dimplex Link hub. Check Dimplex installation instructions for the specific wiring diagram for each model.
Elnur Ecombi wiring — similar three-wire arrangement. The Ecombi's built-in room thermostat sensor is in the heater casing and does not require external sensor wiring. Some installers add an external Elnur thermostat for greater room temperature accuracy in larger rooms.
Legacy two-wire heaters — older storage heaters use only L and N, with no electronic controller. The input charge is set manually each evening using a dial from 0–6 or 0–10. If replacing these with modern heaters, the installer must add the permanent live connection back to the consumer unit.

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06 · Heating Installation Guide

Replacement Costs (2025)

Storage heater replacement costs vary by heater size, brand, and whether new dedicated circuits are required. The following figures represent typical 2025 installed prices in the UK.

Heater unit only (supply) — Dimplex Quantum 2.55 kW: £350–£450; Elnur Ecombi 2.0 kW output: £300–£380. Prices vary by distributor and are subject to change.
Installation (per heater, existing circuit) — £150–£250 per heater to remove old unit, install new heater, connect to existing dedicated circuit, and test.
Installation (per heater, new circuit) — £250–£450 per heater when a new dedicated radial circuit must be run from the consumer unit. Longer cable runs, ceiling voids, or intermediate floors increase cost.
Whole-house replacement (4–6 heaters) — £2,500–£5,500 installed for a typical 3–4 bedroom all-electric property, including new consumer unit if required and all circuits.

ECO4 scheme funding may cover all or a significant portion of storage heater replacement costs for eligible households. Installers must be TrustMark registered and Pas 2030 or Pas 2035 compliant to carry out funded work.

07 · Heating Installation Guide

When Storage Heaters Make Sense

Storage heaters are not always the best heating choice, but they suit specific property and lifestyle profiles well.

Properties without gas supply — storage heaters are a practical alternative to oil, LPG, or electric panel heaters where gas is unavailable and a heat pump is not viable.
All-day occupancy homes — retired occupants or those working from home benefit from daytime heat release. Properties where occupants are absent all day gain little from storage heaters because most heat is released when no one is in.
Competitive Economy 7 tariff — the off-peak rate must be significantly lower than the peak rate to justify storage heaters. Check current Economy 7 and Economy 10 tariff availability from Octopus Energy, EDF, and British Gas before recommending storage heaters to a customer.
Rental properties and social housing — storage heaters require no annual service or gas safety certificate, making them low maintenance for landlords. Modern models have 2–3 year warranties and 10+ year lifespans.

08 · Heating Installation Guide

For Electricians: Storage Heater Replacement Work

Storage heater replacement is steady domestic work that electricians encounter throughout the year, with peaks in autumn before the heating season. ECO4 funded work provides additional volume for TrustMark-registered businesses.

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Use the Elec-Mate certificates app to complete Minor Works Certificates or Electrical Installation Certificates for storage heater replacements on your phone. Clients receive their Building Regulations compliance documents before you leave.

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Storage heater replacement often reveals inadequate consumer units with insufficient spare ways or no RCD protection. Use the quoting app to present a combined storage heater and consumer unit upgrade quote that secures the full job.

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Electric Storage Heater Installation UK: Modern Storage Heaters

Key Takeaways

Modern vs Old Storage Heaters

Get the BS 7671 A4:2026 Cheat Sheet — free

Popular Models: Dimplex Quantum and Elnur Ecombi

Dedicated Circuit Requirements

Economy 7 and Economy 10 Wiring

Thermostat and Charge Control Wiring

Try Elec-Mate free for 7 days

Replacement Costs (2025)

When Storage Heaters Make Sense

For Electricians: Storage Heater Replacement Work

Certificate on Site

Quote Consumer Unit Upgrades Too

Manage storage heater installations with Elec-Mate

Frequently Asked Questions About Storage Heater Installation

What is the difference between a modern storage heater and an old one?

Do storage heaters need to be on their own circuit?

What is Economy 7 wiring and how does it work?

Can I replace old storage heaters myself?

What size MCB do I need for a storage heater?

How much does it cost to run storage heaters?

Can I use storage heaters with a smart meter?

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