Hard coal or wood briquettes: calorific value, cost, emissions and future compared

They sit side by side on the shelf: the bag of hard coal and the pack of wood briquettes. Both promise long-lasting embers, both are heavy, both cost roughly the same. Which is the better choice? The short answer: it depends on the stove. For a wood stove in the living room, the wood briquette; for a coal or slow-combustion stove with the appropriate approval, hard coal is the fuel with the most energy. The long answer, with figures, follows here.

Calorific value: advantage coal – on paper

Hard coal and anthracite deliver 7.5 to 9 kWh per kilogram, wood briquettes around 5 kWh. Per kilo, coal clearly wins. But you do not heat by the kilo, you heat by the kilowatt hour – and what counts is what the fuel costs per kilowatt hour and what the stove makes of it. Coal needs more air, longer heating-up phases and a grate that withstands the high temperatures. A wood briquette releases its energy evenly and gently on the stove.

Cost per kilowatt hour

An example calculation with typical DIY store prices (autumn 2026, bagged goods): hard coal briquettes cost around €0.80 to €1.10 per kilo depending on the region, roughly 10 to 13 cents per kWh. Wood briquettes cost around €0.40 to €0.60 per kilo by the bag, less by the pallet – i.e. 8 to 12 cents per kWh. The supposed calorific advantage of coal disappears in the price. On top of that comes the national CO₂ price, which has also been levied on coal for households since 2023 and will continue to rise in the coming years. Wood, as a renewable raw material, is exempt.

Ash, soot, smell

Hard coal leaves 4 to 8 percent ash, plus clinker that bakes onto the grate. Wood briquettes come in below 1 percent, the ash is fine and can be used as garden fertiliser. The chimney sweep notices the difference too: coal releases more sulphur and soot, the stove glass turns black faster, the chimney needs sweeping more often.

The stove question decides

The most important point is on the type plate of your stove. Most wood stoves sold today are approved for wood and wood briquettes only. Burning coal in them damages the grate and firebrick, can lead to overheating and breaches the operating instructions – in the event of damage, nobody is liable. Only slow-combustion stoves and coal stoves with the appropriate approval may burn coal. If in doubt, ask the chimney sweep or read our article Wood stoves and the BImSchV.

Handling and storage

Wood briquettes are clean, low-dust, packaged and stackable. They absorb moisture, so they need a dry place – then they keep for years. Coal is insensitive to moisture but dirty: coal dust in the cellar, black hands, clinker in the ash pan. Anyone with the stove in the living room knows which variant they would rather have next to the sofa.

Climate and future

Wood from sustainable forestry (FSC®, PEFC™) burns within the carbon cycle: the tree bound the CO₂ that is released when burning, and the forest grows back. Hard coal releases carbon that was locked away for millions of years. Politically, the direction is clear: rising CO₂ price, stricter emission limits for fireplaces, subsidies only for renewable heat. Anyone who wants to heat climate-neutrally chooses wood; anyone who runs a coal stove uses coal responsibly – screened, low-dust and in the right grade.

When hard coal is the right choice

For a slow-combustion stove, a coal-fired cooker or a workshop stove expressly approved for coal, hard coal remains the fuel with the highest energy density: around 8 kWh/kg, embers for many hours, little reloading. That is why HEIZFUXX® offers screened, low-dust hard coal in two grades – fine (5–25 mm) for cookers and small stoves, coarse (25–60 mm) for large fireboxes. For wood stoves, hardwood briquettes such as our RUF or Nestro formats also hold the embers all night – without clinker, without sulphur, without a CO₂ levy. Which briquette suits which purpose is shown in the wood briquette comparison.

Conclusion

Hard coal wins on calorific value per kilo and is the right fuel for stoves built for it: coal stoves, slow-combustion stoves, cookers, workshop stoves. For wood stoves in the living room, wood briquettes are the clever choice: approved, clean, climate-neutral – and at least on a par in price per kilowatt hour. The type plate decides.