How much wood pellet for the winter? Work it out for your house

The shortest honest answer: for a typical Polish detached house it's usually 3–6 tonnes a season, and where in that range you land is decided above all by the building's insulation — not its floor area. A well-insulated 150 m² house can burn less pellet than an uninsulated 100 m² house from the 1970s.

Below we show where that number comes from, so you can calculate it for your own house rather than copy someone else's.

Where the result comes from

Pellet consumption is calculated in two steps.

Step 1: how much energy the house needs in a year. That depends mainly on the construction standard and insulation. The ranges published in Polish heating guides look like this:

House standard	Demand
Well insulated / new	50–70 kWh/m²/yr
Average insulation / older house	90–120 kWh/m²/yr
Old building, no insulation	150–250 kWh/m²/yr

Note the scale of that difference: between a well-insulated house and an old uninsulated building it's more than threefold. That's why any advice along the lines of "count 10 kg per square metre" is misleading — without saying which house is meant, such a number means nothing.

Step 2: converting energy to kilograms. The working assumption is that 1 kWh of heat is about 0.2 kg of pellets. That's a practical value already allowing for the real efficiency of the boiler — not the bare calorific value of the fuel.

Let's calculate three real houses

The formula is simple: floor area × kWh/m²/yr × 0.2 kg ÷ 1000 = tonnes per season.

• 120 m² house, average insulation: 120 × 105 × 0.2 = 2,520 kg, i.e. about 2.5 tonnes
• 150 m² house, well insulated: 150 × 60 × 0.2 = 1,800 kg, i.e. about 1.8 tonnes
• 150 m² house, old building, no insulation: 150 × 200 × 0.2 = 6,000 kg, i.e. about 6 tonnes

Same floor area, more than a threefold difference in the sum. That's exactly why it's worth knowing which band your house is in before you order fuel for a whole season.

Don't want to do it by hand? Our calculator (Polish) does exactly the same operation and immediately converts the result into złoty at today's market price.

What this sum doesn't cover

Let's be honest about the method's limits:

• It's an estimate, not a measurement. The ranges above come from trade guides, not from a building standard or a measured study. Treat the result as a starting point, not a guarantee.
• Domestic hot water. If the same boiler also heats water, add typically a few hundred kilograms a year on top of the calculator's result.
• Your habits and the weather. Indoor temperature, the number of occupants and whether the winter was mild can shift the result by ten to twenty percent either way.
• Boiler efficiency and condition. A neglected, uncleaned boiler burns more than the 0.2 kg/kWh factor assumes.

Practical buying advice

If you're buying pellets for the first time and have no consumption history, don't order the whole season at once. Buy 2–3 tonnes, watch real consumption through the first weeks of frost, and only then buy the rest. You'll come out better than by guessing either way: order too little and you buy more in winter, i.e. usually dearer; order too much and you tie up money in fuel you still have to keep dry somewhere for half a year.

If you want to buy the rest cheaper, it's worth watching prices — their spread between shops can be larger than the difference you'd haggle over. Current rates are in our price table.

Sources

The figures used in this article and in the calculator come from two independent, publicly available Polish heating guides:

• kb.pl — "Ile pelletu kupić na zimę" — energy-demand table by building standard (old buildings 150–250, insulated 80–120, new energy-efficient 40–70 kWh/m²/yr) and the 0.2 kg of pellets per 1 kWh factor, derived there from a calorific value of about 5 kWh/kg (Polish).
• stonegarden.pl — "Ile potrzeba pelletu do ogrzania domu" — ranges of 50–70 kWh/m²/yr for a well-insulated house and 90–120 kWh/m²/yr for an older house of average insulation (Polish).

Both are heating-industry guide content, not technical standards — and that's how we treat them here.