Summary

Night storage heaters (also called electric storage heaters or NSHs) charge up overnight on cheap off-peak electricity — traditionally Economy 7, now increasingly time-of-use tariffs like Octopus Agile or Cosy — and release that stored heat through the following day. They're common in flats, park homes, and properties off the gas grid where running a wet central heating system isn't practical. Pricing this job well matters because tradespeople routinely under-quote it: customers assume "it's just swapping a heater," but the job frequently involves circuit assessment, asbestos risk on pre-1980s units, structural wall-fixing checks (these things are heavy), and Part P notifiable electrical work.

The market has two very different products sitting under the same name. Old-style "brick core" heaters (pre-2000s) are dumb — no thermostat feedback, poor input/output control, and they overheat rooms in mild weather while underheating in cold snaps. Modern High Heat Retention (HHR) units, driven by the 2018 ErP Lot 20 regulations, have electronic charge controllers, room thermostats, and open-window detection built in. Since ErP Lot 20 came into force, low-efficiency storage heaters can no longer be sold new in the UK — this is the single biggest driver of "convert my old heaters" enquiries, alongside customers moving off Economy 7 to time-of-use tariffs that make old dumb-charge units financially pointless.

The other pricing trap: customers conflate "storage heater replacement" with "cheap job" because there's no wet system, no radiators, no boiler. In reality, correctly sizing units, running new radial circuits where the existing wiring is undersized or on a shared circuit, and safely removing old units (weight, asbestos) can make this a multi-day electrical job, not an afternoon swap.

Key Facts

Quick Reference Table

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Job type Typical price range Labour time Notes
Single HHR unit swap (existing circuit, like-for-like) £450–£750 2–4 hrs MEIWC issued, no Part P notification needed if truly like-for-like
Single HHR unit, new dedicated circuit £700–£1,100 4–6 hrs Part P notifiable, EIC issued
2-bed flat, 3 units, mix of swap + new circuits £1,800–£3,200 1–1.5 days Common scenario in ex-council/housing association stock
3-bed house, 5–6 units, full replacement £3,500–£7,500 2–3 days May trigger consumer unit upgrade
Consumer unit upgrade (if required) £600–£1,200 Additional 0.5–1 day Dual RCD or RCBO board, 17–18th edition compliant
Old unit removal, non-ACM £30–£60 per unit Included in labour WEEE disposal via licensed carrier
Old unit removal, presumed/confirmed ACM £150–£400 per unit Separate visit likely Licensed asbestos contractor required for confirmed ACM
Room heat-loss survey / sizing visit £0–£75 30–45 min per room Often folded into quote as a goodwill visit

Detailed Guidance

Sizing units correctly

Undersizing is the single biggest cause of callback complaints on this job. Work from room area, ceiling height, glazing area/type, and insulation standard rather than simply matching the old unit's kW rating — old units were frequently oversized or undersized in the first place because dumb heaters were cheap to overspecify. A reasonable site method: measure floor area (m²), apply 60W/m² for a well-insulated modern room, up to 100W/m² for solid-wall Victorian/Edwardian stock with single glazing, then round up to the nearest standard HHR output (1.25kW, 1.7kW, 2.55kW, 3.4kW). For open-plan living/kitchen areas, consider two smaller units rather than one oversized unit for better heat distribution — quote this as an option, don't decide it for the customer without discussion.

Circuit design and consumer unit capacity

Before quoting, always open the consumer unit and record: total main fuse rating, number of spare ways, whether it's a dual-RCD or RCBO board, and whether there's an existing off-peak (Economy 7) supply with a functioning time switch or RTS receiver. A common false economy is quoting a like-for-like swap when the existing circuit is undersized for a higher-output replacement unit — always check cable csa and length against the new unit's rated current, not just the old unit's. If the RTS signal has been switched off in the area (an ongoing UK-wide phase-out), the off-peak circuit may need converting to a smart time switch or the supplier's replacement off-peak signalling method — flag this to the customer as a possible extra before quoting a fixed price, or price it as a provisional sum.

Asbestos and safe removal

Any storage heater installed before the mid-1980s should be treated as a presumed asbestos-containing material under the Control of Asbestos Regulations 2012 (CAR 2012) until inspected. The risk is in the core insulation boards, not the outer casing — the danger arises from breaking, drilling or grinding these boards during removal. Do not attempt removal yourself if you suspect ACM presence; get a licensed asbestos surveyor to confirm, and if confirmed, a licensed asbestos removal contractor must dispose of it as controlled waste with a consignment note. Quote this as a provisional item ("subject to asbestos survey") rather than guessing — getting this wrong is both a compliance and a personal exposure risk.

Part P notification and certification

New circuits for storage heaters are notifiable electrical work under Part P of the Building Regulations. If you're registered with a competent person scheme (NICEIC, NAPIT, ELECSA, STROMA), self-certify and register the work with your scheme provider — this generates the Building Regulations compliance certificate for the customer without a separate Building Control application. If you're not scheme-registered, the customer (or you on their behalf) must submit a Building Notice to local Building Control before work starts, which adds cost and time to the job — factor the Building Control fee into your quote if this applies. A genuine like-for-like swap on an existing circuit with no new wiring is generally non-notifiable, but issue a Minor Electrical Installation Works Certificate (MEIWC) regardless, per BS 7671 Part 6.

Regional price variation

London and the South East run 20–35% above the ranges quoted here, driven by higher electrician day rates (£300–£450/day vs £220–£280/day in the Midlands/North) and higher parking/congestion overheads in city properties. Rural and off-grid properties (where storage heating is more common because there's no mains gas) sometimes see lower labour rates but higher materials delivery costs and potential extra time for older, harder-to-access consumer units in outbuildings or under-stair cupboards.

Frequently Asked Questions

Can I just swap a storage heater like-for-like without an electrician?

No — even a "simple" swap involves isolating a live circuit, connecting a new load, and confirming the circuit is safe for the new unit's rated current. This is notifiable/certifiable electrical work under Part P and BS 7671. A competent DIYer physically lifting the unit onto the wall isn't the risk — the electrical connection and certification is, and an uncertified installation can cause problems at sale/insurance time for the homeowner.

Do all storage heaters need a dedicated off-peak circuit?

Ideally yes, but not always in practice — some older installations run several units off a single ring or radial that was adequate for old dumb units but is undersized for higher-output HHR replacements. Never assume the existing circuit is adequate; check cable size, length (volt drop), and the combined load against the circuit's protective device rating before signing off a swap.

Why has my customer's old storage heater always run hot even in mild weather?

This is the classic symptom of a dumb (non-HHR) unit with only a manual damper and no electronic charge/output control — it charges a fixed amount overnight regardless of forecast temperature and can't modulate output through the day. This is exactly the failure ErP Lot 20 was designed to eliminate; it's a strong, honest upsell point for HHR replacement rather than a scare tactic.

Is it worth converting from storage heating to a heat pump or gas central heating instead?

Sometimes, but it's a much bigger job and a different conversation — cross-reference night storage heaters vs central heating with the customer before quoting either job, since the right answer depends on whether mains gas is available, the property's insulation standard, and whether the customer is eligible for heat pump grant schemes. Don't let a storage heater enquiry turn into an unplanned heat pump sales pitch — scope it properly first.

What's the risk of getting the tariff wrong?

If the property's off-peak signalling (RTS) has stopped working locally, the customer may be charging heaters at peak rate without realising — this destroys the economics of storage heating entirely and is a common source of "my heating bills are huge" complaints that are actually a signalling fault, not a heater fault. Always check the time switch is actually switching at the right times as part of any storage heater job, even a simple swap.

Regulations & Standards