Pellet Consumption and Heating Cost Calculator

For a 120 m² house with average insulation, approximately 2,554 kg of pellets are needed per season. At a price of 1,200 PLN/tonne the season cost is about 3,065 PLN, giving roughly 438 PLN per month over the 7-month heating season.

Poor insulation requires about 150 kWh/m² per year, average insulation about 100 kWh/m², and good (energy-efficient) insulation about 60 kWh/m². Good insulation can reduce pellet consumption by up to 2.5 times compared with a poorly insulated building.

A1-class wood pellets have a calorific value of 4.6–5.0 kWh/kg. The calculator uses 4.7 kWh/kg as a typical value for pellets available on the market. Higher-quality pellets mean less fuel by weight for the same heat output.

The standard heating season in Poland lasts about 7 months (October to April). It may be shorter in milder regions and longer in the mountains or north-east. The calculator uses 7 months to determine the monthly cost.

Cost-effectiveness depends on energy prices. Pellets typically offer a lower cost per kWh than natural gas at current Polish prices. A Class 5 boiler is eco-friendly, meets emission standards and may qualify for the Clean Air programme subsidy. The downside is the need to store fuel on-site.

The Clean Air programme offers up to 8,000 PLN (basic level) or 13,900 PLN (enhanced level) for a Class 5 pellet boiler. This can be combined with the thermo-modernisation tax relief — a deduction of up to 53,000 PLN from taxable income.

Class A1 is the highest quality — low ash (≤0.7%), high calorific value. Class A2 allows up to 1.5% ash. Class B covers industrial pellets with higher ash content, not recommended for domestic boilers. Always use A1-class pellets for residential heating.

Pellets must be stored in a dry location — moisture causes the granules to disintegrate. A 120 m² house needs roughly 3 m³ of storage space (about 2.5 tonnes). Common solutions include a textile silo or a dedicated room next to the boiler room.

The most effective measures are: insulating walls and the roof, replacing windows with triple-glazed units, installing a weather-compensating thermostat and thermostatic radiator valves, servicing the boiler regularly, and buying pellets in summer when prices are typically lower.

The calculator is optimised for residential buildings. For commercial premises, industrial halls or multi-family buildings, calculations should use specific energy demand figures from a dedicated energy audit of the building.