What does heating cost by fuel?
A ton of coal, a cubic metre of gas and a kilowatt-hour of electricity can't be compared by price per unit. Here is the comparison by the price of usable heat, for every system the calculator supports.
The price of heat compared
The table shows the calculator's default prices, the efficiency assumption and the resulting price of 1 kWh of heat. For the yearly cost we used the example of a house that needs 15,000 kWh of heat.
| System | Assumption | Default price | Price of 1 kWh of heat | Per year at 15,000 kWh |
|---|---|---|---|---|
| Heat pump | COP (coefficient of performance) 4.5 | €0.20/kWh | €0.044 | €667 |
| Gas | calorific value 10.5 kWh/m³ at 92% condensing boiler efficiency | €1.10/m³ | €0.114 | €1,708 |
| Pellets | calorific value 4.9 kWh/kg at 85% boiler efficiency | €300/ton | €0.072 | €1,080 |
| Air conditioning | COP (coefficient of performance) 4.5 | €0.20/kWh | €0.044 | €667 |
| Coal | calorific value 5.6 kWh/kg at 70% boiler efficiency | €260/ton | €0.066 | €995 |
| Wood | calorific value 1700 kWh/stere at 70% boiler efficiency | €70/stere | €0.059 | €882 |
| Direct electric heater | 98% conversion efficiency to heat | €0.20/kWh | €0.204 | €3,061 |
How to read the results
Three things stand out:
- Heat pumps and air conditioners give the cheapest heat (€0.044/kWh), assuming a coefficient of performance of 4.5.
- Wood (€0.059/kWh), coal (€0.066/kWh) and pellets (€0.072/kWh) follow. The differences between them are small, so comfort, storage and fuel availability often decide.
- Gas (€0.114/kWh) is a little more expensive, and direct electric heating (€0.204/kWh) is the most expensive, because 1 kWh of electricity gives at most 1 kWh of heat.
What the table doesn't capture
- The purchase price and installation. Heat pumps and pellet boilers cost more to buy than a gas boiler or an electric heater.
- Your own time and convenience. Coal and wood have to be loaded and stored; pellets and gas are automatic.
- Maintenance and servicing, the chimney, inspections and any connection fees.
- The real efficiency of the equipment, which depends on the condition of the boiler, fuel quality and system settings.
Why prices aren't the same everywhere
The default prices in the calculator are rough averages for Slovakia. The price of wood depends on the species and moisture, pellets are sold in different qualities, and energy prices vary with the supplier and the tariff. That's why it is best to enter your own numbers from your bills.
The numbers in the tables and examples are based on the calculator's default values (rough average prices for Slovakia). Real costs differ with your prices, equipment and house.
Frequently asked questions
Which heating is the cheapest?
At the calculator's default prices, a heat pump gives the cheapest heat, followed by wood, coal and pellets, then gas. Direct electric heating is the most expensive. The order changes with prices in your area.
Why is direct electric heating the most expensive when its efficiency is high?
A direct heater turns 1 kWh of electricity into about 1 kWh of heat. Since electricity costs more per kWh than gas or wood, it comes out the most expensive. A heat pump gets around this by delivering several kWh of heat from 1 kWh of electricity.
Does the comparison include the price of the boiler?
No. It compares only the running cost of heat. The price of the equipment and the payback period are covered by a separate article and the last step of the calculator.