The short answer
Both a heat pump and electric storage heaters run on electricity, but they use it very differently. A storage heater converts electricity directly into heat at 100% efficiency — one unit of electricity gives one unit of heat — charging up overnight on a cheaper Economy 7 rate and releasing heat through the day. A heat pump is far more efficient: with a SCOP of around 3 to 4, it delivers 3 to 4 units of heat per unit of electricity by moving heat from the outside air. That means a heat pump typically uses roughly a third of the electricity for the same heat, so it is usually much cheaper to run despite needing a wet heating system. Storage heaters are cheaper and simpler to install with no pipework, which keeps them common in flats and some off-grid homes.
Electric storage heaters are common in flats and off-gas-grid homes, but heat pumps offer a far more efficient way to use electricity for heat. Here is how they compare.
Heat pump vs storage heaters
- Heat pump efficiencySCOP ~3.0–4.0
- Storage heater efficiency100% (1 unit in = 1 unit heat)
- Electricity used per unit of heatHeat pump uses ~1/3 of storage heaters
- Install complexityHeat pump higher; storage lower
- Hot waterHeat pump heats it; storage heaters do not
Why a heat pump uses far less electricity
A storage heater is a direct electric heater with a thermal store: electricity passes through an element, heats ceramic bricks, and that heat is released over time. Like any direct electric heater, it is 100% efficient at the point of use — but that ceiling means one unit of electricity only ever produces one unit of heat.
A heat pump does not generate heat by resistance; it moves heat from outside to inside using a refrigeration cycle. Because it is moving heat rather than creating it, it can deliver more heat energy than the electricity it draws. A SCOP of 3 to 4 means 3 to 4 units of heat per unit of electricity. For the same amount of heating, a heat pump therefore uses roughly a third of the electricity a storage heater would — which is the core reason it is usually much cheaper to run, even though storage heaters benefit from a cheaper overnight tariff.
| Factor | Air source heat pump | Electric storage heaters |
|---|---|---|
| How it makes heat | Moves heat from outside air | Direct electric resistance |
| Efficiency | SCOP ~3.0–4.0 | 100% at point of use |
| Electricity for same heat | Roughly one third | Three times as much |
| Tariff | Standard or time-of-use | Usually Economy 7 overnight |
| Hot water | Yes, via cylinder | No (separate immersion needed) |
| Up-front cost | Higher (grant available) | Lower |
Indicative comparison for guidance. Sources: Energy Saving Trust.
Comfort, control and hot water
Storage heaters charge overnight and release heat through the day, which can mean the heat runs out by evening or lingers when it is not wanted. Modern high-heat-retention storage heaters with better controls improve this, but the underlying limitation — heat stored hours in advance — remains. A heat pump heats on demand through a thermostat and weather compensation, giving more responsive, even comfort across the day.
Hot water is another difference. Storage heaters only do space heating; hot water typically comes from a separate immersion heater, which is direct electric and relatively expensive to run. A heat pump heats both your home and a hot water cylinder, so it covers domestic hot water efficiently too.
Tariffs and how running costs really compare
Storage heaters are built around a two-rate tariff like Economy 7, charging up overnight on the cheaper rate and releasing heat through the day. That cheap overnight unit price is their main cost advantage, but it only applies to the off-peak hours, and any daytime top-up or boost runs at the more expensive day rate. The heaters also have to guess the next day's heat demand hours in advance, so on a mild day you can pay to store heat you do not need.
A heat pump can also use a time-of-use electricity tariff, shifting some of its consumption — and hot water heating — into cheaper periods, but its bigger advantage is structural: it simply needs far less electricity in the first place because of its SCOP. Three times less energy for the same heat is a larger and more dependable saving than a cheaper overnight rate on three times the consumption.
The honest comparison therefore depends on tariffs as well as efficiency. But in most cases the heat pump's efficiency advantage outweighs the storage heater's off-peak pricing, especially once hot water — often heated expensively by a separate immersion in a storage-heater home — is included.
Installation, cost and suitability
Storage heaters are simple: they bolt to the wall and wire into the electrical supply, with no pipework, flue or outdoor unit. Replacing them is cheap and quick. A heat pump is a wet central heating system — it needs an outdoor unit, pipework, radiators or underfloor heating, and a hot water cylinder — so installation costs more and is more involved.
That up-front gap is offset by the £7,500 Boiler Upgrade Scheme grant in England and Wales for eligible homes, and by lower running costs over time. Suitability depends on the property: a heat pump needs space for the outdoor unit and cylinder and benefits from good insulation. Flats can be harder — outdoor unit siting and freeholder permissions can be obstacles — which is one reason storage heaters remain common in apartments.
Frequently asked questions
Are storage heaters cheaper to run than a heat pump?
Generally no. Storage heaters are 100% efficient, so one unit of electricity gives one unit of heat. A heat pump delivers 3 to 4 units of heat per unit of electricity, so it uses roughly a third of the electricity for the same heat. Even with storage heaters on a cheaper overnight tariff, a heat pump usually wins on running cost.
Can I get a heat pump grant if I currently have storage heaters?
Yes. Homes heated by electric storage heaters are eligible for the £7,500 Boiler Upgrade Scheme grant for an air source heat pump in England and Wales, provided there is a valid EPC with no outstanding insulation recommendations and an MCS-certified installer does the work. Scotland has separate funding through Home Energy Scotland.
Do heat pumps work in flats with storage heaters?
They can, but flats are often harder than houses. You need somewhere to site the outdoor unit and space for a hot water cylinder, and you may need permission from the freeholder or management company. Where those obstacles can be resolved, a heat pump is far more efficient than storage heaters; where they cannot, modern high-retention storage heaters with good controls are the practical fallback.
Sources & further reading
- Energy Saving Trust — air source heat pumps
- Energy Saving Trust — electric storage heaters
- Ofgem — Boiler Upgrade Scheme
Figures on this page are typical UK ranges drawn from published sources and depend on your specific home. They are guidance, not a quotation or guaranteed saving.