Fan Heater Running Cost Calculator
Estimate how much an electric fan heater costs per hour, day, month and winter season using its power rating, thermostat cycling and your electricity rate.
Enter Fan Heater Use
Your Fan Heater Cost
The running cost will appear here with hourly and seasonal figures.
How To Use The Fan Heater Calculator
1Check kW
Read the heater label. If it shows watts, divide by 1000. A 2000 W fan heater is 2 kW.
2Set Real Hours
Enter the time the heater is switched on each day. Use the timer limit if the heater shuts off before that time.
3Use Duty Cycle
If the thermostat cycles the heater off once the room is warm, lower the duty cycle. If the room never reaches temperature, use 100%.
4Compare Settings
Use the second heat setting to see the difference between a 2 kW boost and a 1 kW low setting.
What The Cost Result Means
The monthly figure is based on the heater rating, unit rate, daily use, days per month and thermostat duty cycle. The hourly figure shows the cost if the heater runs at the full selected kW for one hour. The daily and seasonal figures make the number easier to compare with other heating choices, such as using central heating for more rooms, improving draught-proofing or wearing warmer layers while working at a desk.
The result is specific to the settings you enter. A fan heater used for 20 minutes to warm a bathroom is a different cost case from a 2 kW heater used for six hours in a cold room. Thermostats help only if the room reaches the target temperature and the heater actually cycles off. In a draughty or poorly insulated space, the duty cycle can stay close to 100%.
Formula And Method
Effective daily hours = smaller of entered hours and timer limit, unless timer limit is zero.
Daily kWh = heater kW x effective daily hours x duty cycle percentage.
Monthly kWh = daily kWh x days used per month.
Monthly cost = monthly kWh x electricity unit rate.
Season cost = monthly cost x months in season.
Cost per full-power hour = heater kW x electricity unit rate.
The default electricity rate is editable and uses an Ofgem price-cap style example for England, Scotland and Wales direct debit customers in the second quarter of 2026. Enter your actual tariff for a bill-specific result.
Worked Fan Heater Examples
Desk Boost
A 1.5 kW fan heater used for one hour on 70% duty for 18 days a month uses 18.9 kWh. It may be cheaper than heating the whole home for a short work session, but safety and ventilation still matter.
Evening Room Heat
A 2 kW heater used for three hours, 20 days a month, at 80% duty uses 96 kWh a month. That is no longer a tiny add-on to the bill.
All-Day Cold Room
A 2 kW heater at 100% duty for eight hours uses 16 kWh in one day. At a typical electricity unit rate, repeated all-day use can become one of the largest appliance costs in the home.
Fan Heater Cost Table
| Heater Setting | kWh For One Hour | Cost At 24.67p/kWh | Best Use Case |
|---|---|---|---|
| 0.75 kW low heat | 0.75 kWh | About GBP 0.19 | Small top-up where the room is already warm. |
| 1 kW low setting | 1.00 kWh | About GBP 0.25 | Desk, small room or short boost. |
| 1.5 kW setting | 1.50 kWh | About GBP 0.37 | Faster warm-up with thermostat control. |
| 2 kW full setting | 2.00 kWh | About GBP 0.49 | Short bursts only, unless it cycles down. |
| 2.5 kW high setting | 2.50 kWh | About GBP 0.62 | Large or very cold room, with careful monitoring. |
Safety And Practical Checks
Portable fan heaters need clear space around them, stable positioning and careful use near bedding, curtains, clothes, pets and children. Do not cover a heater, do not use it to dry clothes, and avoid extension leads unless the manufacturer and electrical rating allow it. A heater with a tip-over switch, overheat protection and timer can reduce risk, but it does not remove the need for supervision.
If a room needs a fan heater every day, check the cause. Draughts, poor insulation, undersized central heating, broken controls, blocked radiators or open chimney draught can all make electric top-up heating more expensive than it first appears. A cost result above your comfort level is a prompt to review heat loss and heating controls, not just the heater setting.
FAQ
How much does a 2 kW fan heater cost per hour?
At 24.67p per kWh, a 2 kW heater costs about GBP 0.49 for one hour at full power. Enter your own rate for a bill-specific value.
Does a thermostat reduce the cost?
Yes, if it makes the heater switch off for part of the time. Use the duty cycle field to reflect the share of time the element is actually on.
Is a fan heater cheaper than central heating?
For one short room boost, it can be. For long periods, electric resistance heating is often costly, so compare the full usage pattern rather than one hour.
Does the fan itself use much power?
The fan motor is usually small compared with the heating element. The kW rating mainly reflects the heat output.
Should I include standing charge?
No. The heater changes kWh consumption, not the daily standing charge you pay for having an electricity supply.
What if my heater has two settings?
Run the calculator twice, once for each setting, or use the lower-setting field as a comparison. The result depends on how long each setting is used.
Sources
- Ofgem. (2026). Energy price cap explained. Ofgem. https://www.ofgem.gov.uk/information-consumers/energy-advice-households/energy-price-cap-explained
- Electrical Safety First. (n.d.). Portable heaters. Electrical Safety First. https://www.electricalsafetyfirst.org.uk/guidance/product-safety/portable-heaters/
- Energy Saving Trust. (n.d.). Reducing home heat loss. Energy Saving Trust. https://energysavingtrust.org.uk/advice/reducing-home-heat-loss/