Online calculator: what’s cheaper for heating — Gas, Electricity (heat pump) or Wood/Pellets?
How we calculate which energy source is cheapest
This tool compares the running cost of heating with gas, electricity (heat pump/AC), and wood/pellets. We convert everything to one comparable number: the effective cost per usable kWh of heat. The lowest effective cost indicates the cheapest option to run, based on the values you enter.
Electricity:
Electricity: you enter your electricity price per kWh and the SCOP of your heat pump/AC. If you keep “Use outdoor temperature” off, we use SCOP (a seasonal average) and compute: effective cost = electricity price / SCOP. If you enable “Use outdoor temperature”, the tool estimates a COP for your chosen average outdoor temperature (and optionally reduces it for defrost) and computes: effective cost = electricity price / COP. That gives a more period-specific picture, but it is still an approximation.
Gas:
Gas: you enter your gas price per volume unit and the gas energy content. Boilers have losses, so we also apply boiler efficiency. Effective cost per kWh of heat = (gas price / energy content) / boiler efficiency.
Wood / Pellets:
Wood/pellets: you enter the price (by volume or weight), the fuel energy content, and the stove/fireplace efficiency. If pricing is by volume, we first convert volume to weight using the density (kg/m³ or lb/ft³). Effective cost per kWh of heat = fuel price / (usable heat delivered), after appliance efficiency is taken into account.
Conclusion:
After entering your values, the tool compares the effective cost per usable kWh of heat across the selected sources. This lets you quickly see how gas, a heat pump/AC and wood/pellets compare under your assumptions. All results are indicative and do not replace professional advice.
Important notes and limitations
- SCOP is a seasonal average under standardized test conditions. In colder weather, with higher supply temperatures or in real installations, the actual COP can be lower than the SCOP suggests.
- Boiler efficiency depends on boiler type, maintenance, return temperatures and control strategy. Condensing boilers only reach high efficiencies when they can condense (low return temperatures).
- Wood energy content and usable heat depend strongly on moisture content, wood species and how it is burned. Wet wood may look cheap per m³, but because of the water content it delivers much less usable heat and can cause more soot and emissions.
- Results are indicative. Real costs depend on tariffs (fixed vs dynamic), climate, insulation, system design, user behaviour and fuel quality. Always treat the outcomes as an estimate, not an exact prediction.
Practical factors that can strongly affect real-world results
- Heating system supply temperature (lower is usually better for heat pump efficiency)
- Heat distribution system (radiators, underfloor heating, convectors, fan coils, air units)
- Insulation level and air tightness of the building
- Sizing, placement and settings of heat pump/AC and/or stove
- Local climate (temperature, wind, humidity and duration of cold periods)
- How often and how intensively you heat (zones, setpoints, schedules, night setbacks)
- Subsidies, taxes, incentives and time-varying tariffs (day/night, dynamic pricing)
- Wood species or pellet quality and moisture content
- Storage conditions (keeping fuel dry) and local availability
FAQ
How does the calculator compare heating costs?
It converts gas, electricity (heat pump/AC) and wood/pellets into an effective cost per usable kWh of heat, then compares which is lowest.
What is SCOP and why does it matter?
SCOP is seasonal efficiency (heat delivered divided by electricity used). A higher SCOP reduces the effective cost per kWh of heat.
What is COP and why include outdoor temperature?
COP is the efficiency at a specific outdoor temperature. Including outdoor temperature can give a more realistic comparison for a period (e.g., a cold week or an entire heating season).
About & contact
HeatSourceCalc.eu is an independent online calculator for comparing heating costs using gas, electricity (heat pumps or air conditioning), and wood or pellets.
This website is operated by the owner of HeatSourceCalc.eu. Contact: grwwebsitebeheerder@gmail.com
All calculations are indicative and provided for informational purposes only. This tool does not provide financial, energy, or investment advice.
