How many cubic metres of firewood are needed to get through the winter?
This is the question that households heating with wood ask themselves every autumn: how many steres should I order to last until spring? Too few, and you will have to restock in the middle of winter; too many, and the wood will clutter up the woodshed. There is no universal figure, but a few simple concepts can help you estimate your needs realistically.
Understanding the units: stere and apparent cubic meter
The stere
The stere corresponds to a volume of 1 m³ of logs 1 meter long, stacked in an orderly fashion (1 m × 1 m × 1 m), including the empty spaces. It is the historical reference unit in the firewood trade.
Why the volume decreases when cutting wood
When these one-meter logs are cut into shorter pieces, they stack better and the gaps between them decrease. The amount of wood remains the same, but it occupies less space. This is referred to as the apparent cubic meter (ACM or MAV). As an indication, one stere occupies approximately:
- about 0.8 m³ once cut into 50 cm logs;
- about 0.7 m³ for 33 cm logs;
- about 0.6 m³ for 25 cm logs.
These values are commonly accepted orders of magnitude: they vary according to the shape of the logs and the way they are stacked. Above all, remember not to be surprised if "one stere" of 33 cm logs does not fill a cubic meter: it is normal.
Factors that cause your consumption to vary
1. Main or auxiliary heating
This is the most determining criterion. A stove running every day from October to April to heat the whole house will not consume nearly the same amount as a fireplace lit on weekends for ambiance.
2. The surface area and insulation of the home
A recent, well-insulated house may have heating requirements several times lower than those of an old house with uninsulated walls and single-glazed windows. Ceiling height and the layout of the rooms also play a role.
3. The climate of your region
The duration and severity of winter vary greatly between the Atlantic coast, the Northeast, or mountain regions.
4. The efficiency of your appliance
An open-hearth fireplace releases only a small portion of the wood's energy (often around 10 to 20%), with most of the heat escaping through the flue. A modern stove or insert typically reaches 70% and more. Replacing an open hearth with a high-performance appliance can therefore significantly reduce the amount of wood required.
5. The species and moisture content of the wood
A stere of dense hardwoods (oak, hornbeam, beech) contains more energy than a stere of softwood because it is denser. Above all, damp wood heats much less effectively: always aim for wood with less than 20% moisture content. To learn more, read our article Which firewood to choose?
A simple method to estimate your needs
The calculation method
If you know your heating needs in kWh (from a previous heating system invoice, an energy performance certificate, or a thermal study), you can make an estimate:
Number of steres ≈ heating needs (kWh) ÷ (energy of one stere × appliance efficiency)
For a well-dried stere of dense hardwoods, an energy value of around 1,700 to 2,100 kWh is often used (an indicative value, which depends on the species and moisture content).
Purely illustrative example: a home with needs of about 10,000 kWh per year, heated by a stove with 75% efficiency, using wood providing about 2,000 kWh per stere: 10,000 ÷ (2,000 × 0.75) ≈ 6.7 steres. We will round up to 7 steres, plus a small margin.
The experience method
The most reliable method remains your own history. Keep track of the quantity consumed each year and the severity of the winter: after one or two seasons, you will know exactly what to order. If you have just moved in, ask the previous owner or your neighbors who have a similar house and appliance.
Orders of magnitude for guidance
With all the usual caveats, here are some generally observed benchmarks:
- Occasional use (occasional fires, evenings and weekends): often 1 to 3 steres per winter;
- Regular auxiliary heating: often 3 to 5 steres;
- Main heating of a detached house with a high-performance appliance: frequently 6 to 10 steres, more for a large, poorly insulated house or in a harsh climate.
These ranges are indicative and do not replace an estimate based on your specific home.
Our tips for ordering correctly
- Plan for a margin of 10 to 20%: a colder winter than expected can arrive quickly, and dry wood keeps well from one season to the next if stored properly.
- Plan ahead: ordering early in the season allows you to store your wood peacefully and bring it in bone-dry when the first cold weather arrives.
- Choose the right length: 25, 33, or 50 cm depending on the size of your hearth. Logs that are too long require re-cutting; logs that are too short leave unused space.
- Plan the storage space: keep the apparent volume in mind. For example, 6 steres in 33 cm will occupy approximately 4 to 4.5 m³ once stacked.
- Combine fuels if necessary: a few densified logs as a supplement can be helpful at the end of winter. See our comparison Logs, densified logs, or pellets.
In summary
The number of steres required depends primarily on your usage (auxiliary or main heating), the insulation of your home, and the efficiency of your appliance. Remember that the quantity is expressed in steres but that short-cut wood occupies less space; estimate your needs using the formula or your history, add a margin, and always opt for dry wood: it is the best way to consume less.
Ordering your firewood
Discover our steres of dried firewood in 25, 33, and 50 cm, in classic or split logs, in the Firewood & logs collection. To start your fires, also see Charcoal & firelighters.