Night Storage Heaters vs Central Heating: Costs and When to Recommend Each

Summary

This is one of the most common "which system" conversations a heating engineer or general tradesperson has with a landlord or homeowner, particularly on older electric-only flats and off-gas-grid rural properties. Night storage heaters have a poor reputation — largely earned by 1970s-80s models with no real controls, that overheated rooms in the morning and left them cold by evening — but the modern high heat retention (HHR) storage heater required since the 2018 Ecodesign Lot 20 regulations is a genuinely different product: electronically controlled, better insulated, and far more responsive to actual heat demand.

Central heating (in UK trade usage, almost always meaning a gas-fired wet system with radiators, though the term now increasingly includes heat pump wet systems) remains the default recommendation wherever it's achievable, because running costs per unit of delivered heat are lower and the tenant/homeowner has real-time control rather than a system that commits to tomorrow's heat schedule tonight.

This article sets out the cost comparison in practical terms, when storage heaters are still the right call, what "modern" storage heater actually means versus the reputation, and the questions to ask before recommending either route. It should be read alongside system design for wet system design and immersion heater for related Economy 7 wiring context.

Key Facts

• Storage heater principle — ceramic or clay bricks inside an insulated case are heated by an electric element overnight on a cheap tariff, then release stored heat through the day via natural convection and, on modern units, a fan-boost
• Off-peak tariffs — Economy 7 gives roughly 7 hours of cheap-rate electricity overnight (typically midnight–7am, tariff-dependent); Economy 10 gives 10 hours split across night and afternoon
• Typical Economy 7 off-peak rate — around 40-60% of the standard unit rate as of 2026, though this varies significantly by supplier and has narrowed since the 2022-23 energy crisis; always check current supplier rates rather than assume a fixed ratio
• Ecodesign Lot 20 (Commission Regulation (EU) 2015/1188) — since 1 January 2018, all local space heaters (including storage heaters) sold in the UK/EU must have: electronic room temperature control, integrated or connectable open window detection, and a distance/timer control (7-day programmer) — this is what defines a modern "HHR" (High Heat Retention) storage heater vs a legacy manual-input unit
• HHR storage heater efficiency — typically 95%+ conversion of electricity to heat at the point of use (all electric heating is close to 100% efficient at point of use — the cost issue is the price per kWh of electricity, not conversion losses)
• Gas boiler efficiency — modern condensing combi/system boilers 92-94% SEDBUK efficiency; older non-condensing boilers as low as 70-78%
• Gas unit price vs electricity unit price — as a rough multiple, standard electricity is typically 3-4x the price of gas per kWh (both fluctuate with the energy market — always check current Ofgem price cap figures rather than relying on historic ratios)
• Heat pump SCOP — a well-installed air source heat pump delivers a Seasonal Coefficient of Performance of roughly 2.5-4.0, meaning 1 kWh of electricity in produces 2.5-4.0 kWh of heat out — this materially changes the electric-vs-gas cost comparison versus direct electric storage heating
• No flue required — storage heaters need no flue, no gas supply, and no annual gas safety inspection, which simplifies installation in flats and listed buildings
• Weight — a single HHR storage heater can weigh 40-90kg depending on output; floor loading and wall fixing must be checked, particularly in older or timber-floored properties
• Output range — domestic storage heaters typically range from 1.7kW to 3.4kW per unit; a typical UK 3-bed house needs 3-5 units sized per room
• Part P — new circuit installation for storage heaters (dedicated Economy 7 circuit, typically radial wired in 2.5mm² or 4mm² depending on load) falls under Part P notification requirements
• EPC impact — storage heaters typically score worse than gas central heating on EPC (Energy Performance Certificate) SAP calculations due to the higher carbon factor and cost factor historically applied to grid electricity, which can affect MEES compliance for rental properties
• MEES (Minimum Energy Efficiency Standard) — landlords must achieve EPC band E minimum (with proposed tightening to C under review as of 2026); all-electric storage heater properties frequently need additional insulation measures to meet this without a heating system change

Quick Reference Table — Cost & Suitability Comparison

Detailed Guidance

Why storage heaters got a bad reputation

Pre-2018 storage heaters, and particularly units from the 1970s-90s still found in many rental flats, had none of the Ecodesign Lot 20 controls. Common complaints that shaped the reputation:

• Manual input dial only — the occupant guessed how much heat to "charge" the night before, with no feedback on actual room temperature
• No thermostat feedback loop — the unit charged to the dial setting regardless of whether the room was already warm from solar gain or occupancy
• Poor retention — older ceramic cores and thinner insulation meant heat was largely gone by evening, leaving the coldest part of the day (evening, when people are home) under-heated
• No boost control — occupants had no way to release stored heat faster on a particularly cold day, or to hold it back on a mild one

Modern HHR units address all of these directly: electronic thermostats read actual room temperature, open window detection cuts output if a window opens (avoiding wasted heat), and better-insulated cores retain heat for release through the day on a more even curve, with a manual boost fan for immediate extra output when needed.

The core running-cost calculation

The comparison a tradesperson needs to be able to do on the spot, in simple terms:

Storage heater running cost = (property heat demand in kWh) × (Economy 7 off-peak unit rate)

Gas central heating running cost = (property heat demand in kWh) ÷ (boiler efficiency, e.g. 0.92) × (gas unit rate)

Heat pump running cost = (property heat demand in kWh) ÷ (SCOP, e.g. 3.0) × (standard or off-peak electricity unit rate)

Because storage heaters draw pure resistive electric heat (no multiplication effect like a heat pump's SCOP), even a cheap off-peak tariff rarely beats gas on a straight cost-per-kWh-delivered basis once boiler efficiency is factored in. Heat pumps, by contrast, can beat or match gas because the SCOP multiplier offsets electricity's higher unit price — this is the reason a heat pump retrofit is now the default alternative recommendation to storage heaters on an off-gas-grid property, not "better" storage heaters.

Always run the calculation with current supplier tariffs at the time of quoting — the gas/electricity price ratio has moved substantially since 2021 and will likely continue to shift; never quote historic rule-of-thumb figures as if they're current.

When to recommend storage heaters anyway

Despite gas or a heat pump being cheaper to run in most cases, there are legitimate scenarios where storage heaters remain the sensible recommendation:

1. No mains gas and no viable heat pump installation — some flats have no external wall space or right to install an external heat pump unit (leasehold restrictions, no outdoor space, listed building consent refused)
2. Budget-constrained interim measure — a landlord doing a light refurbishment on a tight budget may not have £8,000-£16,000 for a heat pump retrofit; replacing failed 1980s storage heaters with modern HHR units at £3,500-£7,500 is a legitimate stopgap that materially improves both running cost and comfort versus the units being replaced
3. Low or intermittent occupancy — holiday lets, occasional-use annexes, or properties with irregular occupancy patterns don't always suit the "commit to tomorrow's heat overnight" model of storage heating well, but the simplicity (no wet system to freeze/leak when unoccupied) can outweigh the running cost disadvantage
4. Small flats with minimal heat demand — where total annual heat demand is low, the absolute cost difference between storage heating and gas/heat pump may be small enough (a few hundred pounds a year) that installation cost and disruption dominate the decision instead

When to steer the customer away from storage heaters

• Family homes with high daytime occupancy — the classic storage heater failure mode (heat released through the day when the house is empty at work/school, cold by the time everyone's home in the evening) is a real and common complaint even with modern controls, because the physics of "charge overnight, release through the day" doesn't match a working family's actual occupancy pattern
• Anywhere gas is already on-site and functioning — replacing a working gas system with storage heaters is very rarely the right call; flag this clearly if a customer requests it for any reason other than a specific technical constraint
• Rental properties needing to meet or improve MEES/EPC targets — storage heating typically scores worse on EPC than gas or heat pump systems; if the landlord's primary driver is EPC compliance, model both options against the actual EPC calculation before recommending

Installation considerations for modern HHR units

• Dedicated circuit — each storage heater (or bank of heaters) needs a correctly sized radial circuit fed via a dedicated Economy 7 consumer unit split (off-peak-only or dual-rate metering, coordinated with the supplier/DNO meter change)
• Fireproof hearth/floor protection — check manufacturer instructions; most modern units don't require a hearth but do specify minimum clearances to combustible flooring and furnishings
• Wall fixing — verify the wall construction can take the point load of a wall-mounted unit; free-standing units on their own legs avoid this but need floor space
• Positioning — avoid siting directly under a window (heat loss cancels output) or blocked by furniture (restricts convection and can trip thermal cutouts)
• Boost control wiring — some HHR ranges have a separate fan boost circuit; check manufacturer wiring diagrams, as this can require a second cable run to the unit

Retrofit sequencing — replacing old storage heaters with HHR units

1. Survey existing circuits — confirm cable size and route are adequate for new unit load (may differ from old unit)
2. Check meter/tariff setup — confirm Economy 7/10 timing is correctly configured with the supplier; incorrect off-peak timing is a common and easily missed cause of high bills after a "successful" installation
3. Remove old units — note asbestos risk on pre-2000 units (some older storage heater cores and gaskets contain asbestos; treat with caution, see asbestos guidance if in doubt)
4. Install new HHR units to manufacturer spec, on existing or upgraded circuits
5. Commission electronic controls — set target room temperatures, verify open window detection function, and walk the customer through the boost control (this handover step is frequently skipped and is the single biggest driver of "the new heaters don't work properly" callbacks)
6. Leave written or app-based instructions — customers used to the old dial-only units often don't understand modern controls without a walkthrough

Frequently Asked Questions

Are storage heaters cheaper to run than gas central heating?

Almost never on a straight kWh-delivered basis, even with off-peak electricity. A gas boiler converts gas to heat at 90%+ efficiency and gas is priced substantially lower per kWh than electricity (including off-peak). Storage heaters can look competitive in specific tariff/usage scenarios, but the general rule for a tradesperson advising a customer is: assume gas is cheaper to run unless gas isn't available.

Can I convert a house from storage heaters to gas central heating?

Yes, provided mains gas is available or can be connected (via the local gas transporter, e.g. National Grid or Cadent, with a connection charge). This is a full retrofit: boiler, pipework throughout the house, radiators in every room, and a flue. Budget accordingly — this is materially more disruptive and expensive than a storage heater replacement, but usually pays back in running costs and property value over several years. See system design for wet system layout considerations.

What's the difference between Economy 7 and Economy 10?

Economy 7 gives approximately 7 hours of off-peak electricity, almost always overnight (exact hours vary by region and supplier, typically somewhere between 11pm and 8am). Economy 10 splits roughly 10 hours of off-peak time across the night and an afternoon or evening window, which can suit storage heater users better because it allows a partial "top-up" charge later in the day rather than relying entirely on the overnight charge lasting until evening. Not all suppliers offer Economy 10; availability varies by region and DNO.

Do storage heaters need annual servicing like a boiler?

No statutory annual service is required (unlike Gas Safe boiler servicing), but manufacturers recommend periodic checks — inspection of the case, controls, and element condition — every few years, and any fault (unit not charging, control panel error, unusual smell or noise) should be investigated promptly. There's no equivalent Gas Safe Register requirement because there's no combustion or gas safety risk.

Regulations & Standards

• Commission Regulation (EU) 2015/1188 (Ecodesign Lot 20) — mandatory electronic controls, open window detection, and timer function for local space heaters (including storage heaters) sold in the UK/EU since 1 January 2018; retained in UK law post-Brexit

• BS 7671:2018+A2:2022 — IET Wiring Regulations; governs circuit design for storage heater and Economy 7 circuits

• Building Regulations Part P (Electrical Safety — Dwellings) — notification requirement for new dedicated heating circuits

• Building Regulations Part L (Conservation of Fuel and Power) — relevant to overall property efficiency and interacts with heating system choice on major renovations

• Minimum Energy Efficiency Standard (MEES) Regulations 2015 — sets minimum EPC band for rental properties; heating system choice materially affects compliance

• Gas Safety (Installation and Use) Regulations 1998 — governs any gas central heating installation and annual servicing (Gas Safe registered engineer only) — not applicable to storage heaters

• MCS MIS 3005 — heat pump installation standard, relevant where a heat pump is being compared as the alternative to storage heating

• Ofgem — Energy price cap information — current gas and electricity unit rates for cost calculations

• Energy Saving Trust — Storage heaters guidance — consumer-facing guidance on storage heater operation and efficiency

• GOV.UK — Ecodesign for energy-related products — Lot 20 local space heater requirements

• GOV.UK — Minimum Energy Efficiency Standard (MEES) for landlords — EPC compliance requirements

• system design — wet central heating system design: open vent vs sealed, S-plan vs Y-plan

• immersion heater — Economy 7 two-circuit wiring reference, relevant to combined storage heater/immersion installations

• system flush — for properties converting to a wet system, post-installation flush and inhibitor dosing requirements

• epc ratings — EPC band thresholds and SAP calculation method, relevant to the MEES compliance discussion above