Worldwide
Heating cost calculator
Heating is the biggest single energy cost in most homes, and it lands hardest in the colder months when a heater or boiler runs for hours every day.
Enter the unit price in your own currency.
This tool estimates what that heating costs over a whole season so you can budget for it rather than be surprised by a winter bill. It works from three things: the power the heater draws, the hours it is on each day, and how long the heating season lasts. Enter the power in kilowatts, the daily hours, the price you pay per kilowatt-hour, and the number of days you expect to heat, and it returns the cost for the season, the cost per day, a per-month figure, and the total energy used in kilowatt-hours. The reasoning is the same for any heat source that runs on metered energy. A heater rated at 2 kilowatts that runs for 8 hours uses 16 kilowatt-hours of energy in a day, and the cost is that energy multiplied by your unit price. For an electric heater the power is the figure on the label. For a gas boiler the idea still holds, because gas is billed per kilowatt-hour like electricity, but you should use the average power the boiler actually draws rather than its peak output, since a boiler fires in bursts and idles in between rather than running flat out the whole time. People use this to compare the running cost of an electric heater against central heating, to decide whether heating one room is cheaper than the whole house, or to see how much a longer or milder winter changes the total. Because real heating use rises and falls with the outdoor temperature, the insulation of the building and the thermostat setting, the figure is a planning estimate, not an exact forecast.
How it works
- Enter the heater or system power in kilowatts; an electric heater shows this on its label, and a 1,000-watt heater is 1 kW.
- Enter the hours it runs on an average day during the season.
- Enter the price you pay per kilowatt-hour, in your own currency, for the fuel that powers it.
- Set the length of the heating season in days, often around 180 for a temperate winter.
- The tool finds the daily energy as power times hours, multiplies by the price for the daily cost, and scales that across the season.
season cost = power (kW) x hours per day x price per kWh x days
Energy in a day is the power drawn multiplied by the hours it runs, since a kilowatt held for an hour is a kilowatt-hour. Multiplying that daily energy by the price per kilowatt-hour gives the daily cost, and multiplying by the number of days in the season gives the total. Each input enters as a straight multiplier, so halving the hours, the power or the season length halves the cost, and the total energy is the same product without the price.
- power
- heater or system draw in kilowatts, an average for a cycling boiler
- hours per day
- time the heating runs on an average day
- price per kWh
- unit price of the fuel that powers it
- days
- length of the heating season
Typical power of common heaters
| Small plug-in fan or panel heater | about 1 to 1.5 kW | takes the chill off one room |
| Standard electric room heater | about 2 to 3 kW | the common portable size |
| Oil-filled radiator | about 1.5 to 2.5 kW | cycles once warm, so averages less |
| Gas boiler, average draw | often 5 to 15 kW peak | but fires in bursts, so the average is lower |
Worked example
A 2 kW electric heater runs for 8 hours a day, the unit rate is 0.25, and the heating season is 180 days: it uses 16 kWh a day (2 times 8), which costs 4.00 a day, so the season comes to 720 and uses 2,880 kWh in all, about 120 a month while it is running. Drop the daily hours to 4 and the season halves to 360. Heating one room with a 2 kW heater for a few hours is often cheaper than firing a whole-house system, but only if the rest of the home does not then need warming separately.
Key facts
- Heating is usually the largest single energy cost in a home over a year.
- Daily energy is power times hours, so a 2 kW heater for 8 hours uses 16 kWh.
- A gas boiler cycles on and off, so use its average draw, not its peak rating.
- Per kilowatt-hour, electricity typically costs more than gas for the same heat.
Tips
- Heating one occupied room can beat heating the whole house, as long as the rest is left cool.
- Use the heater setting you actually run on, since high and low settings draw very different power.
- A timer or thermostat that cuts the running hours lowers the cost in direct proportion.
- For a gas system, read the kilowatt-hours straight off the bill rather than guessing the boiler power.
Frequently asked questions
How do I find my heater power?+
An electric heater states its power on a label or in the manual, in watts or kilowatts; divide watts by 1,000 to get kilowatts, so a 2,000-watt heater is 2 kW. Many heaters have a high and a low setting, so use the one you actually run on. For central heating, use the average draw rather than the peak rating.
Can I use this for a gas boiler?+
Yes, with care. Gas is billed per kilowatt-hour on the meter, so the same sum works, but a boiler does not run at full power continuously. It fires and idles to hold a temperature, so its average draw over an hour is well below its peak rating. Use a realistic average power, or work backwards from the kilowatt-hours your gas bill shows.
What counts as the heating season?+
It is the stretch of the year when you actually run the heating, which depends on your climate and comfort. A temperate winter might be roughly six months, around 180 days; a milder one less, a harsh one more. Set it to match how long you expect to heat, not the calendar.
Why does my real bill differ from this?+
Because heating demand tracks the weather. A cold snap pushes the hours and the power up, a mild spell pulls them down, and a thermostat that cycles the system on and off means the real average rarely matches a flat daily figure. The result is a budgeting estimate, not a meter reading.
Is electric heating more expensive than gas?+
Per kilowatt-hour of energy, electricity usually costs more than gas, so a like-for-like electric heater can cost more to run than a gas system delivering the same heat. A heat pump changes the picture, because it moves several units of heat for each unit of electricity, but a plain electric heater does not. Compare both on the cost per kilowatt-hour of useful heat.
Does a thermostat or timer change the result?+
It changes the hours, which is the input that matters most here. A timer that runs the heating for fewer hours, or a thermostat that lets it idle once the room is warm, both lower the effective daily hours and so lower the season cost in direct proportion.
Things to watch
- Real heating use swings with the weather, insulation and thermostat, so treat the total as an estimate.
- A boiler rarely runs at its peak rating, so entering the peak power overstates the cost.
- This covers a single heat source at a steady rate; a whole house with several zones needs adding up separately.
Last updated: 2026
This is an estimate for general guidance, not financial, tax, legal or medical advice. Figures can change and individual circumstances vary. Always confirm with an official source before making decisions.
Built and maintained by Vikas Dulgunde. Editorial standards.