Heat batteries cost from £2,500 to £6,000 installed — but few households qualify for the full grant
A heat battery is a sealed unit that stores heat for your radiators and hot water. The average installed cost in the UK ranges from £2,500 for a small 6–8 kWh unit to £6,000 for a larger 15+ kWh system, including VAT at 0% (Energy Saving Trust, 2026). The Boiler Upgrade Scheme (BUS) offers a £7,500 grant for heat pumps but does not cover standalone heat batteries (GOV.UK, 2026).
Heat battery UK costs range from £2,500 to £6,000 installed. The Boiler Upgrade Scheme does not cover standalone batteries, but off-gas-grid homes replacing oil or LPG can see payback in 5-8 years.
- Installed cost ranges from £2,500 for 6 kWh to £6,000 for 15+ kWh.
- Boiler Upgrade Scheme covers heat pumps only, not standalone batteries.
- Pairing a battery with a heat pump unlocks the full £7,500 grant.
- Off-gas-grid homes pay back within 5 to 8 years replacing oil or LPG.
- Round-trip efficiency hits 90 to 97% with phase-change salt hydrate materials.
- Heat batteries cost from £2,500 to £6,000 installed — but few households qualify for the full grant
- Quick numbers — heat battery specs and savings at a glance
- Heat batteries store off-peak electricity as heat for later use — no water or chemicals
- You qualify for a heat battery grant only if you pair it with an eligible heat pump
- The direct answer to "heat battery UK" — it is a phase-change thermal store that cuts electricity bills by 30–50% if charged on a time-of-use tariff
- Only MCS-certified installers can fit a heat battery under the grant scheme — check the register before you pay
- Heat batteries work best in well-insulated homes with a time-of-use electricity tariff
- Heat batteries have a 15–20 year lifespan with no routine maintenance — but the PCM can degrade
Households installing a heat battery alongside an eligible heat pump can claim the full £7,500 grant for the heat pump, but the battery itself must be paid for separately. Off-gas-grid homes replacing oil, LPG, or electric storage heaters are the primary candidates for cost recovery within 5–8 years (DESNZ, 2026). If you are on mains gas and want only a heat battery with no heat pump, you get zero grant support.
Quick numbers — heat battery specs and savings at a glance
| Specification | Typical value | Source |
|---|---|---|
| Storage capacity range | 6–15+ kWh | MCS product database, 2026 |
| Round-trip efficiency | 90–97% | Energy Systems Catapult, 2026 |
| Charge power input | 3–9 kW | Manufacturer datasheets (Sunamp, tepeo, Mixergy) |
| Space footprint | 0.05–0.15 m² floor area | EST product fact sheet, 2026 |
| Annual running cost (electricity) | £400–£700 for typical 3-bed home | Ofgem typical domestic consumption values + Octopus Agile tariff data, 2026 |
| Typical payback period vs gas combi boiler | 8–15 years (no grant) | DESNZ domestic RHI successor analysis, 2026 |
Heat batteries store off-peak electricity as heat for later use — no water or chemicals
A heat battery uses a phase-change material (PCM), typically a salt hydrate, that stores heat at a constant temperature by melting and releasing it when it solidifies (Energy Systems Catapult, 2026). Unlike a hot water cylinder, a heat battery does not lose heat through standing losses. Manufacturers claim 90–97% round-trip efficiency (Sunamp technical datasheets, 2026).
The stored heat is transferred via a heat exchanger to your central heating system or hot water supply. It operates at flow temperatures of 55–65°C (MCS 024 installer standard, 2026). There is no need for a flue, gas pipe, or external unit. The battery is a sealed indoor appliance that can be wall-mounted or floor-standing.
Compare heat batteries vs hot water cylinders
You qualify for a heat battery grant only if you pair it with an eligible heat pump
The Boiler Upgrade Scheme (BUS) provides £7,500 towards an air-source or ground-source heat pump installed by an MCS-certified installer. The heat battery is an eligible ancillary component but does not attract its own grant payment (GOV.UK BUS guidance, 2026). To receive the full £7,500, you must replace a fossil-fuel heating system (gas, oil, LPG, or electric storage heaters) with a heat pump and heat battery combination.
The heat battery must be MCS-certified and listed on the MCS product database to qualify as part of the heat-pump installation (MCS 024, 2026). Households in England and Wales can apply via the BUS portal. Scotland has a separate Home Energy Scotland grant of up to £7,500 for heat pumps, again covering the battery only as part of the system (Home Energy Scotland, 2026). If you are on mains gas and want only a heat battery with no heat pump, you get zero grant support — the battery must be fully self-funded.
It is a phase-change thermal store that cuts electricity bills by 30–50% if charged on a time-of-use tariff
A heat battery works by charging during cheap off-peak hours, such as Economy 7, Octopus Cosy, or Agile, and discharging heat on demand throughout the day (Octopus Energy tariff comparison, 2026). Typical savings compared to a standard electric boiler or storage heaters are 30–50% on annual heating costs, assuming the battery is charged at 7–10p/kWh and discharged at peak rates of 25–30p/kWh (DESNZ domestic fuel cost comparison, 2026; Ofgem price cap data, Q1 2026).
The battery delivers consistent heat at 55–65°C without the temperature drop that storage heaters suffer. This makes it suitable for both radiators and hot water. It is not a replacement for a gas boiler in terms of upfront cost, but it removes the need for a gas connection and flue, which can save £1,000–£2,000 in new-build scenarios (NHBC cost guide, 2026).
Only MCS-certified installers can fit a heat battery under the grant scheme — check the register before you pay
To qualify for the BUS grant, the entire heat-pump system including the heat battery must be installed by a company registered with the Microgeneration Certification Scheme (MCS) (MCS installer database, 2026). The installer must also be TrustMark-registered for consumer protection (TrustMark scheme rules, 2026). You can verify an installer’s MCS status at mcs-certified.com. The product itself must appear on the MCS product directory.
If you are installing a heat battery without a heat pump (no grant), MCS certification is not legally required but is strongly recommended for warranty validity and insurance compliance. For electrical connections, the installer must be registered with NICEIC or NAPIT if the battery requires a new circuit or consumer unit modification (Part P of the Building Regulations, 2026).
Heat batteries work best in well-insulated homes with a time-of-use electricity tariff
The payback period drops below 10 years only in homes with an EPC rating of C or better. In poorly insulated dwellings, the battery’s stored heat is lost faster and savings evaporate (EST in-situ monitoring report, 2026). Homes with solar PV panels benefit further. The battery can be charged directly from solar generation, reducing grid electricity consumption by 40–60% during summer months (Energy Systems Catapult, 2026).
The battery is most cost-effective for households currently using electric storage heaters, LPG, or oil. Replacing these with a heat battery and heat pump can cut annual heating bills by £500–£1,200 (DESNZ fuel cost comparison, 2026). Homes on a single-rate tariff at a flat 24p/kWh will see minimal savings. The battery’s economic case relies entirely on time-of-use pricing.
Best time-of-use tariffs for heat batteries
Heat batteries have a 15–20 year lifespan with no routine maintenance — but the PCM can degrade
Manufacturers warranty heat batteries for 10 years on the PCM core and 5 years on electronics (Sunamp and tepeo warranty documents, 2026). The phase-change material is designed to last 15–20 years without replacement, though real-world data is limited to lab testing and early adopter installations (EST field trial report, 2026). There are no moving parts, flues, or combustion, so annual servicing is not required, unlike a gas boiler.
The main failure mode is PCM degradation after repeated cycling near the material’s melting point. Manufacturers claim less than 5% capacity loss over 10,000 cycles (Energy Systems Catapult, durability testing, 2026).
Frequently Asked Questions
Installed costs range from £2,500 for a 6-8 kWh unit to £6,000 for a 15+ kWh system, according to the Energy Saving Trust (2026). This includes 0% VAT.
No, the Boiler Upgrade Scheme (BUS) offers a £7,500 grant for heat pumps only, not standalone heat batteries (GOV.UK, 2026). You can claim the grant for a heat pump and pay for the battery separately.
Heat batteries achieve 90-97% round-trip efficiency, according to Energy Systems Catapult (2026). This is higher than a hot water cylinder which has standing heat losses.
Typical payback is 8-15 years for a gas combi boiler replacement with no grant (DESNZ, 2026). Off-gas-grid homes replacing oil or LPG can recover costs within 5-8 years.
Yes, heat batteries can integrate with existing gas boilers to store excess heat, but you get zero grant support if you are on mains gas without a heat pump (GOV.UK, 2026).
