How Much Electricity Do Electric Heaters Use in the UK?
Most portable electric heaters use between 0.5kWh and 2.5kWh per hour, depending on their wattage. Use the calculator below to estimate your cost per hour, day, week, month and winter season using your own electricity rate.
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Quick Answer: How Much Electricity Does an Electric Heater Use?
A typical electric heater in the UK uses between 0.5kWh and 2.5kWh of electricity per hour. At a default electricity rate of 24.67p per kWh, a 2kW heater costs about 49p per hour to run at full power, while a 1.5kW heater costs about 37p per hour.
The real cost depends on heater wattage, how long it runs, your tariff, insulation, room size and whether the thermostat cycles on and off after the room reaches temperature.
Electric Heater Running Cost Quick Table
This table shows estimated costs at 24.67p/kWh. Replace this with your own tariff if your electricity rate is different.
| Heater wattage | Electricity used per hour | Cost per hour | Cost for 4 hours | Best used for | Risk if overused |
|---|---|---|---|---|---|
| 500W | 0.5kWh | £0.12 | £0.49 | Personal heat, desk area, feet | Too weak for a full room |
| 1,000W / 1kW | 1kWh | £0.25 | £0.99 | Small room, short sessions | Slow heat-up in cold spaces |
| 1,500W / 1.5kW | 1.5kWh | £0.37 | £1.48 | Bedroom or home office | Costly if left on daily |
| 2,000W / 2kW | 2kWh | £0.49 | £1.97 | Quick room heating | High monthly cost |
| 2,500W / 2.5kW | 2.5kWh | £0.62 | £2.47 | Short bursts only | Very expensive for long use |
These estimates assume the heater runs continuously at full rated power. Thermostats, eco modes and room temperature can reduce actual usage.
Electric Heater Running Cost Calculator
Enter your heater wattage, electricity unit rate and usage pattern. The calculator estimates your cost per hour, day, week, month and a 120-day winter period.
How We Calculated These Heater Running Costs
We use the standard electricity cost formula:
For example, a 2,000W heater is a 2kW heater. If it runs for one hour at a unit rate of 24.67p/kWh:
What can make your real cost different?
- Thermostat cycling: the heater may switch on and off once the room reaches temperature.
- Insulation: draughty rooms lose heat faster and force the heater to work harder.
- Room size: a small bedroom costs less to heat than a large open-plan room.
- Your tariff: fixed tariffs, Economy 7 and standard variable tariffs can all differ.
- Heater type: fan heaters, convectors, ceramic heaters and oil radiators distribute heat differently.
What This Means in a Real UK Home
In practice, a 2kW heater does not always draw 2kW every minute if it has a working thermostat. In a small insulated bedroom, it may heat the room quickly and then cycle on and off. In a cold conservatory, garage, hallway or draughty room, it may run almost continuously.
Best-case scenario
Small room, door closed, decent insulation, thermostat set sensibly. The heater reaches temperature and cycles off regularly.
Worst-case scenario
Large open room, poor insulation, draughts, heater running on full power for several hours. Costs can rise quickly.
This is why two households using the same electric heater can see very different results. The wattage tells you the maximum draw; your home conditions decide how often the heater needs to work.
How Much Does a 2kW Electric Heater Cost to Run in the UK?
A 2kW electric heater uses 2kWh of electricity per hour if it runs continuously at full power. At 24.67p/kWh, that works out at approximately 49p per hour.
| Usage | Estimated cost |
|---|---|
| 1 hour | £0.49 |
| 4 hours | £1.97 |
| 8 hours | £3.95 |
| 4 hours/day for 30 days | £59.21 |
Direct answer
A 2kW heater is not automatically “bad”, but it becomes expensive when used as a long-duration heating solution. It is best for short, targeted heating rather than all-day use.
How Much Does a 1,500W Heater Cost per Hour?
A 1,500W heater uses 1.5kWh per hour at full power. At 24.67p/kWh, it costs about 37p per hour.
| Usage | Estimated cost |
|---|---|
| 1 hour | £0.37 |
| 4 hours | £1.48 |
| 6 hours | £2.22 |
| 4 hours/day for 30 days | £44.41 |
A 1.5kW heater can be a better fit than a 2kW heater for smaller bedrooms, home offices and short evening sessions.
Electric Heater Running Costs by Type
Most electric heaters are close to 100% efficient at turning electricity into heat, but they feel different in use. The main difference is not magic efficiency; it is heat delivery, controls and how long you leave them running.
| Heater type | Typical wattage | How it heats | Best for | Watch out for |
|---|---|---|---|---|
| Fan heater | 1.5kW–2kW | Fast warm air | Quick bursts | Can be expensive if left on for hours |
| Oil-filled radiator | 1.5kW–2.5kW | Slower, steadier warmth | Longer sessions in one room | Slow to heat from cold |
| Convector heater | 1.5kW–2kW | Warms air through convection | Bedrooms and small living rooms | Can lose heat quickly in draughty rooms |
| Ceramic heater | 1kW–2kW | Fast localised heat | Desk, home office, small spaces | Not ideal for large rooms |
| Halogen heater | 400W–1.2kW | Radiant personal heat | Heating the person, not the room | Needs careful placement and safe use |
For product-level recommendations, see our guide to the best energy-efficient heaters UK.
Real UK Electric Heater Running Cost Examples
Example 1: Small home office
Heater: 1kW ceramic heater
Usage: 2 hours per day, 5 days per week
Estimated weekly cost: about £2.47
Example 2: Bedroom in the evening
Heater: 1.5kW convector heater
Usage: 3 hours per evening, 5 days per week
Estimated weekly cost: about £5.55
Example 3: Cold living room
Heater: 2kW fan heater
Usage: 5 hours per day, 7 days per week
Estimated weekly cost: about £17.27
Example 4: Poorly insulated room
Heater: 2.5kW oil-filled radiator
Usage: 6 hours per day, 7 days per week
Estimated weekly cost: about £25.90
Why Heater Running Costs Vary So Much in UK Homes
Room size
A heater that works well in a small bedroom may struggle in a large open-plan living room.
Insulation and draughts
Poor insulation makes the heater work harder because warm air escapes quickly.
Thermostat behaviour
A heater with a thermostat may reduce actual consumption once the room reaches temperature.
Your tariff
A fixed tariff, standard variable tariff or Economy 7 setup can change your real cost per kWh.
Common Mistakes That Make Electric Heaters Expensive
- Running a 2kW heater all day: the cost compounds quickly.
- Heating a draughty room: warm air escapes before the room stabilises.
- Ignoring the electricity unit rate: small p/kWh differences matter over winter.
- Using fan heaters for long sessions: they are better for fast bursts, not all-day heating.
- Leaving doors open: you end up heating hallways and unused spaces.
- Not using a timer or smart plug: accidental overuse can add noticeable cost.
A simple timer or energy-monitoring smart plug can help control usage. Read our guide to the best smart plugs UK for options that can track energy use.
Which Electric Heater Is Cheapest to Run?
The cheapest electric heater to run is usually the one with the lowest wattage that still does the job. But “cheapest per hour” is not always the same as “best value”. A heater that is too weak may need to run for longer.
| Situation | Usually best option | Why |
|---|---|---|
| Heating yourself at a desk | Low-wattage ceramic or heated throw | Targets the person instead of the whole room |
| Short burst in a small room | Fan or ceramic heater | Fast warm-up, then switch off |
| Longer steady warmth | Oil-filled radiator with thermostat | Slower but steadier heat |
| Controlling usage | Heater + timer or smart plug | Prevents accidental long running time |
Is It Cheaper to Use an Electric Heater or Central Heating?
For heating one occupied room for a short time, an electric heater can make sense. For heating several rooms for many hours, central heating is often the more practical option, especially in homes with gas central heating.
| Option | Usually better for | Usually worse for |
|---|---|---|
| Electric heater | One room, short periods, targeted heat | Whole-home heating, long daily use |
| Gas central heating | Multiple rooms, family use, longer sessions | Heating only one small room briefly |
| Heated throw | Personal warmth while sitting | Actually heating the room |
| Oil-filled radiator | Steady warmth in one room | Fast heat from cold |
For a direct cost comparison, see our guide: Electric Heater vs Oil Radiator Cost UK.
When an Electric Heater May Not Be the Best Choice
An electric heater may not be cost-effective if you need to heat several rooms for many hours every day. In that case, you should first look at insulation, draught proofing, heating controls and whether your central heating can be used more efficiently.
- Avoid using portable electric heaters as your main whole-home heating system.
- Do not use high-wattage heaters in poorly insulated rooms without addressing draughts.
- Do not leave portable heaters running unattended.
- Do not assume a “low energy” label means it is cheap to run all day.
How to Reduce Electric Heater Electricity Usage
Use a thermostat
A thermostat helps prevent the heater running at full power after the room is already warm.
Use a timer or smart plug
Timers prevent accidental long sessions and help you measure real consumption.
Close doors
Heating one closed room is much cheaper than heating connected spaces.
Block draughts
Draught excluders and sealed gaps reduce heat loss and make the heater work less.
Use lower heat once warm
Start higher if needed, then reduce the setting once the room reaches a comfortable temperature.
Heat the person first
For desk work or sofa use, personal warmth can be cheaper than heating the whole room.
Best Next Step Depending on Your Situation
| Your situation | Best next step | Recommended guide |
|---|---|---|
| You need to heat one room | Choose an efficient heater with thermostat and timer | Best Energy-Efficient Heaters UK |
| You want to lower heating costs | Compare heating methods and reduce wasted heat | Cheapest Way to Heat a Room UK |
| You already own a heater | Track real usage with a smart plug | Best Smart Plugs UK |
| You are comparing heater types | Check running cost differences and comfort style | Electric Heater vs Oil Radiator Cost UK |
Electric Heater Safety Notes
Portable heaters can be useful, but they need to be used carefully. Cost is not the only issue; placement and supervision matter.
- Keep heaters away from curtains, bedding, paper and furniture.
- Do not dry clothes on or directly beside a heater.
- Place the heater on a stable, level surface.
- Do not leave portable heaters unattended.
- Do not leave them on while sleeping unless the manufacturer clearly states it is safe.
- Avoid cheap extension leads and overloaded sockets.
- Follow the manufacturer’s manual for clearance, usage and maintenance.
Sources and Editorial Notes
We use public UK energy data, standard electricity formulas and safety guidance to keep this guide practical and transparent.
- Ofgem: Energy price cap unit rates and standing charges
- Ofgem: Energy price cap explained
- Energy Saving Trust: Electric heating
- Energy Saving Trust: Energy data
- Electrical Safety First: Portable heater safety
Last reviewed: 15/05/2026. Electricity rates change over time, so always check your own tariff before making a buying decision.
Frequently Asked Questions
How much electricity does a 2kW heater use?
A 2kW heater uses 2kWh of electricity per hour if it runs continuously at full power. At 24.67p/kWh, that costs about 49p per hour.
Is a 1,500W heater expensive to run?
A 1,500W heater costs about 37p per hour at 24.67p/kWh. It can be reasonable for short sessions, but daily long use can become expensive over a month.
Do electric heaters use electricity when the thermostat switches off?
When the heating element switches off, electricity use usually drops significantly. However, some controls, lights or fans may still use a small amount depending on the model.
Is it cheaper to use a lower-wattage heater?
Per hour, yes. A lower-wattage heater uses less electricity. But if it takes much longer to warm the room, the total saving may be smaller than expected.
Are oil-filled radiators cheaper than fan heaters?
Not automatically. A 2kW oil-filled radiator and a 2kW fan heater use the same maximum electricity at full power. The difference is how they deliver heat and how often the thermostat cycles.
Should I use an electric heater instead of central heating?
It can make sense if you only need to heat one room for a short period. If you need to heat several rooms for hours, central heating may be more practical and often better value.
Can a smart plug reduce electric heater costs?
A smart plug does not make the heater itself more efficient, but it can reduce waste by scheduling usage, switching the heater off automatically and measuring real consumption.
Final Verdict: Calculate First, Then Choose the Right Heating Setup
Electric heaters are best for targeted, short-duration heating. Before buying or using one heavily, calculate the running cost, check your tariff and think about the room you are trying to heat.
If your goal is to reduce bills, the smartest setup is usually not just a better heater. It is a combination of the right heater, thermostat, timer, draught control and disciplined usage.