Quick answer
Gas is cheaper than electricity per kWh, so central heating is cheaper for heating the whole house. But if you're only using one room, for example working from home or spending the evening in the lounge, a plug-in heater in that room is often cheaper than running the boiler for the whole house.
Quick checklist
- How many rooms do you use in the evening?
- Is your boiler gas, oil or electric?
- What is your electricity unit rate?
- Can you close doors to keep heat in one room?
The maths
Gas costs roughly a quarter of the price of electricity per kWh. But a typical gas boiler might use 1–2 kWh or more an hour heating a whole house, while a 1200W heater uses at most 1.2 kWh, and less with a thermostat, to heat one room.
When a plug-in heater wins
- Working from home in one room
- Evenings in one room
- Bedrooms before bed
- Rooms the radiators don't reach well
When central heating wins
- Whole family spread across the house
- Very cold spells
- Keeping the fabric of the house warm and damp-free
What it costs to run (current UK prices)
At the Ofgem price cap of 26.32p per kWh (1 October to 31 December 2026), a 1200W heater like the K1 costs about 32p an hour at full power. Once the room is warm the thermostat switches the heater on and off, so in normal use it averages about 16p an hour.
| How long | Typical cost per day | Over 30 days |
|---|---|---|
| 1 hour | 16p | £4.74 |
| An evening (4 hours) | 63p | £18.95 |
| A working day (8 hours) | £1.26 | £37.90 |
Your own price may be a little higher or lower depending on your region and tariff. See how we calculate running costs or try the running cost calculator with your own unit rate.
The numbers: gas vs electricity
At the October–December 2026 price cap, gas costs about 7.97p per kWh and electricity about 26.32p per kWh. So each unit of heat from electricity costs roughly three times more than from gas.
That means central heating is usually cheaper for heating the whole house. A plug-in heater wins when you'd otherwise heat a whole house just to sit in one room.
A sensible way to combine them
- Keep the central heating on a lower setting so the house doesn't get damp or cold
- Turn down radiators in rooms you're not using
- Use a plug-in heater to top up the room you're in
- Close the door to that room
- Use the thermostat on the heater rather than full power
When to keep the heating on
Don't let the whole house get very cold to save money, especially if anyone in the home is older, very young or unwell. Cold, damp homes can lead to mould and health problems. The NHS suggests heating the rooms you use to at least 18°C.
How the K1 compares with other heaters
| Heater type | Warm in | Running cost | Safety and comfort |
|---|---|---|---|
| Ofenwerk K1 (ceramic) | About 2 seconds | About 16p/hour typical | Tip-over and overheat cut-off, cool-touch case, no glowing coil |
| Coil fan heater (2–3kW) | Seconds | 53–79p/hour at full power | Hot coil, can smell of burnt dust, often noisy |
| Oil-filled radiator (1.5–2.5kW) | 20–30 minutes | 39–66p/hour at full power | Surfaces get hot, heavy to move |
| Convector (2kW) | 10–15 minutes | About 53p/hour at full power | Heat rises to the ceiling first |
| Electric blanket (100W) | 10–20 minutes | About 3p/hour | Warms the bed only, not the room |
Full-power costs worked out at 26.32p per kWh. Thermostats lower all of these in real use.
Using any electric heater safely
These tips follow UK fire-service and Electrical Safety First advice and apply to any portable heater, including ours:
- Plug the heater straight into a wall socket. Don't use an extension lead or adaptor; they can overheat.
- Keep it at least 1 metre from curtains, bedding, clothes and furniture.
- Stand it on a flat, hard, stable surface where it can't be knocked over.
- Never cover it or dry clothes on it.
- Switch it off at the wall when you go out.
- Check the plug and cable now and then. Stop using it if either is damaged or feels hot.
- Make sure you have a working smoke alarm on every floor. Many UK fire services fit them free for older residents.
When the K1 is not the right choice
We'd rather you buy the right heater than return ours. The K1 is probably not for you if:
- You want to replace central heating for the whole house. The K1 heats the room you're in, not every room at once.
- You heat every room in the evening. Central heating will be cheaper.
- You want to heat a large open-plan space over about 20 m² with one heater. Two K1s, or a bigger heater, will do a better job.
Our pick: the Ofenwerk K1 Heater
- Warm air in about 2 seconds (PTC ceramic)
- 1200W, heats rooms up to 20 m²
- Tip-over and overheat cut-offs, cool-touch casing
- Thermostat + remote, about 16p an hour typical
- Free UK delivery, 30-day money back, 24-month warranty
Frequently asked questions
Should I turn off central heating completely?
No. Keeping the house at a low background temperature helps prevent damp. Use a plug-in heater to top up the room you're in.
Is it cheaper to use a plug-in heater or central heating?
For one room for a few hours, a plug-in heater is often cheaper. For several rooms or the whole house, gas central heating is usually cheaper.
Can a plug-in heater replace my boiler?
No. It's designed to heat one room. Keep your central heating for the rest of the house and hot water.
Will using a plug-in heater lower my gas bill?
It can, if it lets you turn the central heating down or off in rooms you don't use. Your electricity bill will rise a little in return.
What about heat pumps?
Heat pumps are very efficient for whole-home heating but cost much more to install. A plug-in heater is a low-cost way to heat one room.
Sources and how we checked this guide
- Electricity price: Ofgem: energy price cap unit rates and standing charges, checked 25 October 2026.
- Heater safety: UK fire and rescue service advice and Electrical Safety First guidance on portable heaters.
- K1 figures (1200W, about 2-second warm-up, room size up to 20 m², safety cut-offs) come from the product specification.
- Costs are worked out with the method on how we calculate running costs.