Costs and comparisons
Electric heater or central heating?
The short answer
Per unit of energy, gas is roughly a quarter the price of electricity in the UK. Yet heating one room electrically often costs less than a central heating cycle. Both statements are true, and the reason is how much space you are warming.
Written and checked by the RapidHeat UK team · Last updated September 2026 · how we work out running costs
Key takeaways
- Gas is cheaper per unit of heat; electric heating is cheaper when you only need one room.
- Roughly: gas around 6–7p per kWh, electricity around 27p per kWh — but the boiler heats the whole house.
- The switch-over point is about two to three rooms.
The prices we are working from
- Electricity: about 27p per kWh
- Gas: about 7p per kWh
Check your own bill — rates move with the cap and your tariff.
One room, one evening
| Scenario | Energy used | Approximate cost |
|---|---|---|
| 1.2 kW electric heater, 4 hours in one room | Up to 4.8 kWh electricity at continuous full power | Up to about £1.30; thermostat cycling may reduce this |
| Gas boiler heating a 3-bed house for 4 hours | Often 15–25 kWh gas | About £1.05–£1.75 |
This example shows why room count matters, but it is not a universal winner. Boiler output, efficiency, controls, insulation, tariffs and how often the electric heater cycles all change the result.
The break-even point
There is no universal room-count break-even point. Electric spot heating is most competitive for one enclosed room over a limited period; gas central heating becomes more competitive as more rooms need heat. Use your own tariff and measured usage rather than treating two or three rooms as a fixed threshold.
Where each option genuinely wins
| Situation | Better choice |
|---|---|
| Working from home alone in a study | Electric heater |
| Bedroom for an hour before bed | Electric heater |
| Whole family at home on a Sunday | Central heating |
| Protecting pipes across the whole house in a hard frost | Central heating on low |
| Extension, conservatory or loft the radiators never reach | Electric heater |
| Boiler broken or awaiting repair | Electric heater |
The mixed strategy most people end up with
Set the thermostat a degree or two lower than usual, turn radiator valves down in unused rooms, and use a plug-in heater in whichever room is actually occupied. That combination gives you comfort where you are without automatically warming every room. Whether it lowers your bill depends on what it replaces and how long each system runs.
What about heat pumps?
An air source heat pump delivers roughly three units of heat per unit of electricity, which changes the maths in its favour for whole-home heating. It does not change the case for spot heating a single room in a house that does not have one.
RapidHeat in this picture
RapidHeat is built for the "one room, right now" case: about five minutes to useful warmth, a thermostat so it is not drawing full power all evening, and a timer so it stops when you stop. Multi-packs cover more than one room — see prices and bundles.
What about turning radiators down instead?
Turning thermostatic radiator valves down in unused rooms is free and effective, and should be the first thing you do. But the boiler still fires, the pipes still lose heat, and the cycle still uses energy. For one room over a short period, compare the plug-in heater's metered use with the boiler's actual gas use rather than assuming either is always cheaper.
A word on storage heaters
Storage heaters on Economy 7 can be economical when charged during the correct off-peak window. That is a different use case from on-demand spot heating, and it is worth comparing your own day and night rates before choosing.
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- 30-day money-back guarantee
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Worth being straight about: RapidHeat is built for rooms up to about 12 m². It is not a replacement for central heating and it will not transform an open-plan lounge or an uninsulated garage. If it is not right for your room, send it back within 30 days.
Questions people ask
- Is it cheaper to heat one room with electric than use gas central heating?
- Usually yes. Running a 1.5 kW electric heater for two hours costs roughly 80p at 27p per kWh. Running a gas boiler to heat an average home for two hours generally costs more than that, because you are heating every room.
- When is central heating the better choice?
- When you need several rooms warm, when the whole family is home, or in very cold weather where an electric heater has to run flat out for hours.
- Can I use both?
- That is what most people end up doing: central heating at a lower temperature for the house, plus one electric heater for whichever room needs extra warmth.
- Should I turn radiators off in unused rooms?
- Turning them down rather than fully off is usually recommended, to keep rooms above the temperature where damp and mould appear.
Stop heating empty rooms
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