Running costs · Updated October 2026
Plug-In Heater Running Costs UK: What It Really Costs Per Hour
Work out exactly what a plug-in heater will add to your bill, with a calculator, ready-made cost tables and honest answers on '1p per hour' claims.
Quick answer
A 1.5 kW plug-in heater costs about 41p per hour at full power on a 27p per kWh tariff, and about 27p per hour at 1.0 kW. Thermostat cycling lowers real costs. Heating one small room for a few hours is usually cheaper than heating the whole house.
Disclosure: Advertorial. We're not the manufacturer or seller and may earn a commission from links to getrapidheat.co.uk.
In this guide
Running cost calculator
Enter how long you'll use it, the power setting and your unit rate.
Running cost calculator
Per day
£1.62
Per week
£11.34
Per month
£48.60
1.5 kW × 4 h × 27p = £1.62 a day at full power. A thermostat usually lowers real costs once the room is warm.
The formula
Cost per hour = power (kW) × unit rate (£ per kWh)
A 1.5 kW heater on full uses 1.5 kWh each hour. At 27p per kWh that's 1.5 × £0.27 = £0.405, about 41p. Your unit rate is on your bill. We use 27p as an example close to recent price cap levels. Check Ofgem for the current figure.
Cost tables at 27p per kWh
| Usage | 1.0 kW (low) | 1.5 kW (high) |
|---|---|---|
| 1 hour | 27p | 41p |
| 2 hours | 54p | 81p |
| 4 hours | £1.08 | £1.62 |
| 8 hours | £2.16 | £3.24 |
| 2 hours/day for a week | £3.78 | £5.67 |
| 2 hours/day for a month (30 days) | £16.20 | £24.30 |
| 4 hours/day for a month (30 days) | £32.40 | £48.60 |
The truth about "1p per hour" heaters
"1p per hour" is one of the most searched heater phrases, and one of the most misleading. At 27p per kWh, 1p buys about 37 watt-hours of electricity. That's like running a 37-watt bulb for an hour. It's not enough to warm a room.
Claims like this usually rely on:
- A tiny heater (often under 100 W) that won't warm a room.
- Counting only the minutes the thermostat is "on" in an already warm room.
- Old or unrealistic electricity prices.
A useful room heater uses roughly 0.5–2 kW while heating. Ignore any advert promising pennies a day for real warmth.
Want a heater with a thermostat and timer to keep running costs down?
See RapidHeat price →Plug-in heater vs central heating
Gas costs much less per kWh than electricity, so gas central heating is usually cheaper per unit of heat. But central heating warms every room. If you're home alone working in one room, heating only that room can cost less overall.
| Scenario | Likely cheaper |
|---|---|
| Whole family home all evening | Central heating |
| One person working in one room all day | Plug-in heater in that room (heating off or low) |
| Quick warm-up of a bedroom before bed | Plug-in heater on a timer |
| Large, draughty room | Central heating or a larger heater |
Read more in plug-in heater vs central heating.
Plug-in vs other electric heaters
Per kW, every electric resistance heater costs the same to run: a 1.5 kW oil-filled radiator and a 1.5 kW ceramic heater both cost about 41p per hour at full power. The differences are how quickly they warm you and how well they hold heat. See our heater types comparison.
7 ways to cut running costs
- Heat only the room you're in and close the door.
- Use the low setting once the room is warm.
- Set the thermostat to a comfortable 18–21°C rather than maximum.
- Use the timer so it never runs when you're not there.
- Block draughts around doors and windows.
- Draw curtains at dusk.
- Check whether a cheaper tariff or off-peak rate suits you.
RapidHeat running cost
The RapidHeat Heater runs at about 1.0 kW (low) or 1.5 kW (high), so roughly 27p–41p per hour at full power on a 27p tariff. That's typical for its size, not magic. Its thermostat and timer help you avoid paying for heat you don't need. See the full RapidHeat guide or prices and bundles.
Frequently asked questions
How much does a plug-in heater cost to run per hour?
Multiply the power in kW by your electricity rate. A 1.5 kW heater at 27p per kWh costs about 41p per hour at full power. A 1.0 kW setting costs about 27p per hour. With a thermostat cycling, the real cost is usually lower.
Are there really 1p per hour heaters?
Not for meaningful room heating. At around 27p per kWh, 1p buys about 37 watt-hours, which is less than a single old-style light bulb. Claims like this usually rely on very low power, unrealistic usage or misleading maths.
Is a plug-in heater cheaper than central heating?
Per unit of heat, gas central heating is usually cheaper than electric heating. A plug-in heater can cost less overall when you heat one room instead of the whole house.
How much does it cost to run a heater all day?
Running a 1.5 kW heater non-stop for 8 hours uses 12 kWh, about £3.24 at 27p per kWh. A thermostat will reduce that in a reasonably insulated room.
Do plug-in heaters use a lot of electricity?
They're among the bigger loads in a home while they run, similar to a kettle but for longer. The key is to run them for short periods in small rooms.
What is the cheapest electric heater to run?
All electric resistance heaters turn nearly all their electricity into heat, so the cheapest to run is the one that heats only the space you need, for only as long as you need, with good thermostat control.
How do I find my electricity rate?
It's on your bill or energy app as the unit rate in pence per kWh. Ofgem publishes the current price cap rates. Fixed tariffs can differ.
How much does RapidHeat cost to run?
At about 1.5 kW on high, roughly 41p per hour at 27p per kWh, or about 27p per hour on the 1.0 kW low setting. The thermostat and timer can bring this down.
Opens getrapidheat.co.uk · Free tracked UK delivery · 30-day money-back guarantee (per seller)
How we researched this guide
We read the official seller's product page, delivery and returns information, and guidance from UK bodies such as Ofgem, the Energy Saving Trust and Electrical Safety First. We have not lab-tested the RapidHeat Heater, and we don't publish customer reviews we can't verify. Anything the seller claims is labelled as their claim. Last reviewed: October 2026.