How the comparison works
Enter your current heating
Choose what you heat with today (coal, pellets, wood, gas, electricity or a heat pump) and add your yearly consumption or what you pay.
The calculator works out the price of heat
It converts your consumption into usable heat in kWh, so fuels with different units and efficiencies can be compared fairly.
Compare with other systems
You see what the same heat would cost with other systems and, if you have a quote, how long the investment takes to pay back.
What does 1 kWh of heat cost?
Fuels are sold in different units (tons, m³, kWh), so they can't be compared by price per unit. What you compare is the price of usable heat per kWh. The table shows the calculator's default values.
| System | Assumption | Default price | Price of 1 kWh of heat |
|---|---|---|---|
| Heat pump | COP (coefficient of performance) 4.5 | €0.20/kWh | €0.044 |
| Gas | calorific value 10.5 kWh/m³ at 92% condensing boiler efficiency | €1.10/m³ | €0.114 |
| Pellets | calorific value 4.9 kWh/kg at 85% boiler efficiency | €300/ton | €0.072 |
| Air conditioning | COP (coefficient of performance) 4.5 | €0.20/kWh | €0.044 |
| Coal | calorific value 5.6 kWh/kg at 70% boiler efficiency | €260/ton | €0.066 |
| Wood | calorific value 1700 kWh/stere at 70% boiler efficiency | €70/stere | €0.059 |
| Direct electric heater | 98% conversion efficiency to heat | €0.20/kWh | €0.204 |
Prices are rough averages (Slovakia) that you can adjust in the calculator to match your own bills. Actual costs depend on fuel quality, equipment efficiency, region and supplier.
Why compare the price of heat, not the price of fuel
A ton of pellets, a cubic metre of gas and a kilowatt-hour of electricity are completely different units, and every appliance turns energy into heat with a different efficiency. A heat pump produces several kWh of heat from one kWh of electricity, while a pellet boiler does not use all the energy in the fuel.
That is why the calculator converts everything into kWh of usable heat. Only then is it clear whether gas, pellets, wood or electricity is cheaper, and how much you would save per year by switching.
Articles and comparisons
In-depth articles on heating costs, heat pumps and investment payback.
Frequently asked questions
How is the cost of heating calculated?
Fuel consumption is multiplied by the fuel's calorific value and the appliance's efficiency, giving usable heat in kWh. The price of heat is the yearly payment divided by that amount. For a heat pump, the coefficient of performance (COP) is used instead of efficiency.
Is a heat pump cheaper than gas?
With the calculator's default prices, yes — running a heat pump comes out far cheaper. The gap does depend on energy prices, the real COP and the heating water temperature. You can see exact figures in the calculator or in the article Heat pump vs gas.
Are the prices in the calculator exact?
They are rough average prices for Slovakia. You can overwrite each one with the figure from your own bill, including decimals. The result is an estimate, not an offer or a binding calculation.
Can I also calculate the payback of a new heating system?
Yes. If you have a quote for a new system, enter it in the last step of the calculator. It shows how long the investment takes to pay back from the yearly saving.