What It CostsHeat Pump vs Electric Heater
This is the largest single running-cost difference in a house, and it rests on one idea that sounds like a trick.
100% efficient is the worst you can do
An electric resistance heater — ceramic, oil-filled, fan, panel, baseboard, immersion element — converts electricity to heat at exactly 100%. Every watt in becomes a watt of warmth. There is nothing wasted and no room for improvement, which is why one 1,500 W heater costs precisely the same to run as any other.
A heat pump does something different. It does not make heat, it moves it: a refrigeration cycle run backwards, taking warmth from the outdoor air and delivering it indoors. Because moving heat takes far less energy than creating it, one unit of electricity delivers two and a half to three and a half units of heat.
The measure is the coefficient of performance: heat out divided by electricity in. Resistance heating is exactly 1. A modern air-source heat pump is 2.5–3.5 in mild weather.
What that does to a bill
The same room, the same warmth, eight hours a day for a 90-day winter:
| Heating with | Electricity a season | At $0.17 | At £0.25 | At €0.35 |
|---|---|---|---|---|
| Resistance heater, COP 1 | 2,592 kWh | $441 | £648 | €907 |
| Heat pump at COP 2.5 | 1,037 kWh | $176 | £259 | €363 |
| Heat pump at COP 3 | 864 kWh | $147 | £216 | €302 |
| Heat pump at COP 3.5 | 741 kWh | $126 | £185 | €259 |
Every row delivers identical heat. Over a decade, the gap between the first and third rows exceeds the installed cost of a mini split in most markets.
Where the comparison breaks down
Cold weather. COP falls as it gets colder — a unit at 3.5 in autumn may be at 2 near freezing, and below its balance point a resistance backup heater runs at a COP of 1. That is why the honest figure to ask a supplier for is the capacity and efficiency table at your design temperature, not the headline number.
Installation. A plug-in heater costs $50 and works tonight. A mini split costs several thousand and needs an installer. The running-cost gap pays that back, but over years rather than months, and faster where electricity is expensive.
One room versus a house. For an occasional cold snap in one room, a resistance heater is the right tool: cheap, immediate, and the annual hours are too few for the running cost to matter. It is heating a house all winter that makes the difference enormous.
Against gas. A heat pump at COP 3 beats a 90% efficient gas boiler when electricity costs less than roughly 3.3 times gas per unit. In North America that is usually comfortable; in parts of Europe where electricity carries heavy levies it can be close.
Put your own numbers in: space heater · heat pump. The two pages take the same inputs, so the only thing that changes between them is the electricity each one needs to do the same job.