Storage heaters have a mixed reputation, many people remember the clunky, draughty units of the 1980s that were either too hot in the morning or stone cold by evening. Modern high-heat-retention (HHR) storage heaters are a different product entirely: heavily insulated, app-controlled, and genuinely efficient at making use of cheap overnight electricity.

They’re not right for every home, but for flats, off-gas properties, and homes with a time-of-use electricity tariff, they deserve serious consideration.

How Storage Heaters Work

Storage heaters charge up during off-peak hours (seven hours overnight on Economy 7, at times that depend on your supplier, your tariff and where you live, or the cheap window of another time-of-use tariff) by resistively heating a ceramic or magnetite core.1 That heat is then released gradually throughout the day. The difference between old and new units comes down to insulation and control:

  • Old-style storage heaters (broadly, models sold before ecodesign rules for local space heaters took effect on 1 January 2018) used simple input and output dials.2 Heat leaked continuously regardless of demand, leading to overheating early in the day and cold evenings.
  • Modern HHR storage heaters have much better insulation, so more of the night’s charge lasts into the evening, plus electronic thermostats, charge predictors, and in many cases Wi-Fi connectivity for app or voice control.

For an EPC, SAP defines a high heat retention storage heater as one that keeps at least 45% of its heat when tested to BS EN 60531, with a timer, an electronic room thermostat, a fan to control output and the ability to estimate the next day’s heating demand.3

Comparison: Old vs Modern Units

FeatureOld-style (pre-2018)Modern HHRSmart HHR
Heat retentionPoor: much of the charge leaks out during the dayAt least 45% (the SAP test)At least 45% (the SAP test)
ControlsManual input/output dialsElectronic thermostatApp + voice control, scheduling
Charge predictionNoneBasicAutomatically adjusts to weather forecasts
Compatible tariffsEconomy 7Economy 7, Octopus Go, AgileAll ToU tariffs
Typical unit price (supply only)-From about £700From about £700 (around £890 for a 1 kW Dimplex Quantum)
Typical lifespan15–25 years20–25 years20–25 years

A 1 kW Dimplex Quantum, a widely sold high heat retention model, was listed at £889.02 including VAT at a national plumbing merchant in September 2026.4

Running Costs

The economics depend almost entirely on your off-peak rate, and the price cap does not set it on its own: on a multi-rate tariff like Economy 7, the peak and off-peak rates together cannot be more than the cap.5 Off-peak rates therefore vary by supplier and region, so check yours before deciding. A typical storage heater draws about 1–3.5 kW during the charging window: Dimplex rates its Quantum range at about 1 kW to 3.3 kW.6

Example for a 2 kW unit charging for 7 hours a night over a 180-night heating season, which is 2,520 kWh:

  • Every 1p/kWh on your off-peak rate costs about £25 a season per unit: £252 at 10p, £378 at 15p

Compare this with:

  • Electric panel heater running 2 kW for 5 hours a day on the standard capped rate of 26.32p/kWh for 1 October to 31 December 2026: 1,800 kWh, roughly £475 per heating season per unit5
  • Gas central heating (for comparison): Ofgem’s typical medium-use home uses 9,500 kWh of gas a year, about £760 at the capped 7.97p/kWh before the standing charge7

On these assumptions the storage heater is cheaper to run on any off-peak rate below about 19p/kWh, and the saving shrinks as the rate rises. Neither is as cheap as an air-source heat pump on the right tariff.

Grant Funding

The Energy Company Obligation (ECO4), which runs to 31 December 2026, can fund heating upgrades, including replacement storage heaters, for low-income, fuel-poor and vulnerable households.8 The Great British Insulation Scheme (GBIS) closed on 31 March 2026 and is no longer taking applications.9 ECO4 eligibility criteria include:

  • Receiving a qualifying benefit, such as Universal Credit, Pension Credit or Housing Benefit10
  • Or a referral from your local authority under ECO Flex10
  • And in every case a home that needs energy efficiency upgrades, as confirmed by a retrofit assessment10

Eligibility does not guarantee that a supplier will install anything, but in qualifying cases units and installation can be fully funded.10 Check your energy supplier’s website or GOV.UK’s Find ways to save energy in your home service.11

Smart Tariff Compatibility

Modern storage heaters are increasingly designed for dynamic tariffs, not just Economy 7:

  • Octopus Go / Intelligent Go, fixed cheap overnight window, compatible with most HHR heaters.
  • Octopus Agile, half-hourly pricing; smart heaters can be programmed to charge only during the cheapest periods. Prices on some nights fall far below the standard capped rate.
  • Other suppliers’ time-of-use tariffs with a cheap overnight window work the same way.

If you’re off-gas and serious about storage heating, switching to a dynamic tariff is the single biggest lever you can pull on running costs.

When Storage Heaters Make Sense

Storage heaters are a strong choice when:

  • You are off the gas grid and heat pumps aren’t feasible (rental property, top-floor flat, listed building)
  • You have an Economy 7 or time-of-use meter, or can get a smart meter, which your supplier installs at no charge12
  • Your property has good insulation (EPC C or above) so retained heat isn’t escaping through the fabric
  • You want individual room control without the cost of a full wet central heating system

They are a weaker choice if:

  • Your property is poorly insulated (heat won’t be retained)
  • You need heating on demand at unpredictable times (storage heaters release heat whether you’re there or not)
  • A heat pump is feasible, a properly sized ASHP on the right tariff will nearly always be cheaper to run

Installation and Regulations

Storage heaters are hardwired, usually with each unit on its own dedicated circuit from the consumer unit.6 A new circuit is notifiable electrical work under Part P of the Building Regulations in England, so it must be self-certified by an electrician registered with NICEIC, NAPIT or another scheme authorised by government, or else notified to Building Control before work starts.1314

Typical installation costs:

  • Per unit: the heater itself, from about £700 for a high heat retention model, plus the electrician’s time and any new circuit15
  • Consumer unit upgrade (if additional ways needed): £500–£1,000 extra
  • Full 4-bedroom house with 6 units (new circuits from scratch): the heaters alone come to about £4,200 or more (6 × £700) before circuits and labour

Replacement like-for-like on existing circuits is simpler and cheaper: Which? puts an electrician’s labour for a replacement storage heater from about £70 where the wiring is already in place, on top of the heater.15

Leading Products in 2026

Without naming specific brands, look for these features:

  • BEAB-approved or equivalent CE-marked product with documented thermal efficiency
  • Listed as high heat retention in the Product Characteristics Database: for an EPC, a storage heater only counts as high heat retention if its brand name and model are in that database.16
  • Built-in 24/7 programmable thermostat with temperature calibration
  • Demand control / auto-charge adjustment
  • Compatible with smart tariffs and IFTTT/API integration if you want home automation

Units with pre-built Home Assistant, Amazon Alexa, or Google Home integration are increasingly available.

Summary

ScenarioVerdict
Off-gas flat on Economy 7Excellent option, especially with smart HHR unit
House with EPC E/F, ECO4 eligiblePotentially free, check immediately
Rented propertyGood for tenants and landlords: predictable running cost
Well-insulated home on gasHeat pump likely beats storage heaters on running cost
Frequent irregular occupationBetter options exist (ASHP, electric panel + smart thermostat)

Modern storage heaters are a significant upgrade over their predecessors and deserve more credit than their reputation suggests. The key is pairing them with the right tariff, without cheap overnight electricity, the economics don’t work.

References (16)

Figures in this note were checked against the sources below on 2 October 2026. Superscript numbers in the text point to them. Every source the site cites, by topic.

  1. 1technicalfairCitizens Advice, guidance.RN-OPLNYMCitizens Advice consumer guidance on storage heaters and time-of-use tariffs. It says Economy 7 gives a lower rate for 7 hours at night and that the exact times depend on supplier, tariff and location.
  2. 2technicalvery strongThe National Archives (legislation.gov.uk), guidance.RN-MXSUBQThe retained ecodesign regulation for local space heaters, which by Article 2(11) includes electric storage heaters; Article 3 applies its requirements from 1 January 2018, the dividing line the note uses.
  3. 3technicalstrongBRE on behalf of the Department for Energy Security and Net Zero, guidance.RN-5IL2BKSAP 10.2 section 9.2.8 defines a high heat retention storage heater: heat retention of at least 45% to BS EN 60531, with a timer, electronic room thermostat and fan-controlled output.
  4. 4costsupplier figureCity Plumbing.RN-YCI3RWA price, true at 2026-09. A builders' and plumbers' merchant product page for one high heat retention storage heater, the 1 kW Dimplex Quantum QM100RF. It shows the supply-only price including VAT.
  5. 5technicalvery strongOfgem.RN-YYE8U2The live source for any running-cost sum in a heating note. For 1 October to 31 December 2026 the direct debit cap is 26.32p per kWh for electricity with a 54.83p daily standing charge, and 7.97p per kWh for gas with a 29.68p daily standing charge, giving a typical annual dual fuel bill of £1,723, a 4% rise on the previous period. Ofgem states these are the average unit rate and standing charge for direct debit customers in England, Scotland and Wales; gas prices include 5% VAT while electricity carried no VAT in this period. The cap is reset every three months, so any note quoting a pence-per-kWh figure should be dated against this page.
  6. 6technicalsupplier figureGlen Dimplex Heating and Ventilation, guidance.RN-FC3ZIXThe maker's installation and operating instructions for the Dimplex Quantum high heat retention storage heater range. It gives each model's charging input rating and states the heaters must be hardwired, not plugged in.
  7. 7technicalvery strongOfgem, guidance.RN-KDJBDBOfgem's letter announcing the price cap for October to December 2026. It states the 2026 typical domestic consumption values used for bills, including 9,500 kWh of gas a year at medium use.
  8. 8technicalvery strongOfgem.RN-FPPUSLECO4 is the fourth phase of the Energy Company Obligation across Great Britain. It applies to measures installed from 1 April 2022 and runs until 31 December 2026 following a nine-month extension; ECO3 closed on 31 March 2022 and ECO4 came into force in July 2022. The scheme places a Home Heating Cost Reduction Obligation on medium and large energy suppliers to promote measures that improve the ability of low-income, fuel-poor and vulnerable households to heat their homes, funding insulation and heating upgrades for both homeowners and tenants. Ofgem also lists the Great British Insulation Scheme as a separate obligation on this page.
  9. 9technicalvery strongOfgem.RN-RDOIJRThe scheme, formerly known as ECO+, ran from April 2023 to 31 March 2026 and is now closed. It obliged medium and large energy suppliers to deliver measures reducing energy use in the least energy-efficient homes in Great Britain. Eligibility was homes with an EPC rating of D to G in Council Tax bands A to D in England, or A to E in Scotland and Wales, plus low-income and vulnerable households. Unlike ECO4, which funds whole-house packages, GBIS mostly delivered a single insulation measure per home. This is the page to cite when a note has to say a grant route has closed rather than leave a reader chasing it.
  10. 10technicalvery strongOfgem, guidance.RN-VI0CLPOfgem's ECO page for householders lists the qualifying benefits, including Universal Credit, Pension Credit, Housing Benefit and Child Benefit, and the local authority Flex referral route.
  11. 11technicalvery strongGOV.UK, guidance.RN-5338K3The government's own recommendation tool, and the neutral link a DIY insulation note should offer instead of a comparison site. It gives personalised home improvement recommendations for property owners in England and Wales, and for each suggestion shows an estimated cost of making the improvement and how much could be saved on bills. It cross-refers to the Boiler Upgrade Scheme, the Warm Home Discount Scheme and the Winter Fuel Payment. A telephone helpline is available Monday to Friday 8am to 6pm except bank holidays, and Saturday 9am to 12pm. The page itself carries no eligibility criteria or scheme figures, so a note quoting grant values must cite the individual scheme pages rather than this one.
  12. 12technicalvery strongDepartment for Energy Security and Net Zero (GOV.UK), guidance.RN-J09YM7GOV.UK guidance for households on smart meters. It states that suppliers must offer smart meters and that you will not be charged for the installation.
  13. 13technicalvery strongMinistry of Housing, Communities and Local Government.RN-SAMO3MThe official list of competent person schemes whose members can self-certify certain building work instead of getting building regulations approval, published 4 April 2013 and last updated 12 March 2018. Named schemes with contact numbers include ATTMA, APHC, Assure Certification, Blue Flame Certification, the British Board of Agrement, BESCA, Capita Gas Registration and Ancillary Services trading as Gas Safe Register, CIGA, Certass, Certsure LLP trading as NICEIC, the Elmhurst Airtightness Scheme, Fensa Limited, HETAS Limited, NAPIT Registration Limited, the National Federation of Roofing Contractors trading as CompetentRoofer, and OFTEC. Two footnotes matter: the Gas Safe Register is not technically a competent person scheme although in practice its installers carry the same building regulations responsibilities, and Benchmark Certification Limited ceased to operate as a competent person scheme on 10 February 2017, becoming part of NAPIT Registration Limited that day. Installers joining an electrical scheme are added to the single electrical competent person register.
  14. 14technicalvery strongMinistry of Housing, Communities and Local Government.RN-JYJ3I5The document that decides what electrical work a homeowner may legally do themselves, and the exact list of notifiable jobs. Regulation 12(6A), reproduced at paragraph 2.5, makes only three things notifiable: the installation of a new circuit, the replacement of a consumer unit, and any addition or alteration to existing circuits in a special location. Regulation 12(9) defines special location as, in a room containing a bath or shower, the zone extending vertically from finished floor level to 2.25 metres (or the shower head position if higher) and horizontally 600mm from the edge of the bath tub or shower tray. Paragraph 2.7 states that all other electrical installation work is not notifiable, namely additions and alterations to existing installations outside special locations, and replacements, repairs and maintenance anywhere. Paragraph 2.8 gives worked examples: a built-in cooker is not notifiable unless a new cooker circuit is needed, and connecting an electric gate or garage door to an existing isolator is not notifiable but running a new circuit from the consumer unit to that isolator is. Paragraph 2.2 confirms Part P reaches outdoor work including fixed garden lighting, pond pumps and outbuildings such as sheds, detached garages and domestic greenhouses. Notifiable work must be certified by self-certification by a registered competent person, third-party certification, or a building control body (paragraph 3.1), with the compliance certificate issued within 30 days (paragraph 3.4). Note that Approved Document P is a source of guidance rather than a ban: non-notifiable work still has to comply with BS 7671.
  15. 15costfairWhich?.RN-W2ZADFA price, true at 2026-09. Which? consumer guide to storage heaters. It gives typical purchase prices (basic models under £400, advanced ones upwards of £700) and the electrician's labour for a replacement on existing wiring.
  16. 16technicalstrongBRE (Building Research Establishment), guidance.RN-860NRPThe rulebook an EPC assessor actually works to, dated 21 August 2025, and the document that explains why two assessors can produce different EPCs on the same house. Convention 1.01 states that RdSAP is used to produce Energy Performance Certificates for existing dwellings only, with new build using full SAP instead. The header sets out the hierarchy that matters most in a dispute: where any Convention conflicts with the relevant published SAP specification, the Convention takes precedence. This edition is for use with RdSAP 10, while RdSAP 2012 assessments use v11.4, and it directs assessors to use RdSAP v10 Table 32 when referring to fuel prices. Each convention carries its own issue and amendment history, so an assessor's treatment of a given element can be dated precisely.

  1. Using storage heaters and immersion heaters, Citizens Advice, accessed 2 October 2026. citizensadvice.org.uk

  2. Commission Regulation (EU) 2015/1188, Article 3: Ecodesign requirements and timetable, legislation.gov.uk, accessed 30 September 2026. legislation.gov.uk

  3. The Government’s Standard Assessment Procedure for Energy Rating of Dwellings, SAP 10.2, BRE on behalf of the Department for Energy Security and Net Zero, accessed 30 September 2026. files.bregroup.com

  4. Dimplex Quantum HHR Control Storage Heater 1 KW QM100RF, City Plumbing, accessed 2 October 2026. Priced at 2026-09 and left there. cityplumbing.co.uk

  5. Energy price cap unit rates and standing charges, Ofgem, accessed 29 September 2026. ofgem.gov.uk

  6. Quantum Series Heater: installation and operating instructions, Glen Dimplex Heating and Ventilation, accessed 2 October 2026. dimplex.co.uk

  7. Summary of changes to the energy price cap, 1 October to 31 December 2026, Ofgem, accessed 2 October 2026. ofgem.gov.uk

  8. Energy Company Obligation (ECO), Ofgem, accessed 13 September 2026. ofgem.gov.uk

  9. Great British Insulation Scheme, Ofgem, accessed 13 September 2026. ofgem.gov.uk

  10. Energy Company Obligation (ECO): homeowners and tenants, Ofgem, accessed 30 September 2026. ofgem.gov.uk

  11. Find ways to save energy in your home, GOV.UK, accessed 7 September 2026. gov.uk

  12. Smart meters: a guide for households, Department for Energy Security and Net Zero (GOV.UK), accessed 30 September 2026. gov.uk

  13. Competent person scheme: current schemes and how schemes are authorised, Ministry of Housing, Communities and Local Government (GOV.UK), accessed 2 October 2026. gov.uk

  14. Approved Document P, Electrical safety: Dwellings, 2013 edition, Ministry of Housing, Communities and Local Government, accessed 30 September 2026. assets.publishing.service.gov.uk

  15. Storage heaters explained, Which?, accessed 2 October 2026. Priced at 2026-09 and left there. which.co.uk

  16. Conventions (v 12.1) for RdSAP 10, BRE, accessed 29 September 2026. bregroup.com