Firewood: Rope, Stere, Cubic Metre… How to Properly Calculate your Purchase (so as not to be fooled)
Autumn is approaching (and so is winter): it’s time to stock up on logs for firewood. But finding your way between the different units of measurement is not always easy.
With autumn arriving (and winter as well), many households anticipate the drop in temperatures by building up their log reserves. According to ADEME, these are close to 7.5 million households in France who use wood as a heating source.
But when placing your order, a question often comes up: how not to make a mistake in the different units of measurement offered? Between stere, rope or cubic metre, it is not always easy to navigate. We take stock.
One stere is not equivalent to one cubic metre
>Let’s talk about a stere already, “an old unit of measurement for firewood”, says Frédéric Pechavy, member of the French Federation of Fuels, Fuels and Heating (FF3C).
One stere corresponds to “a volume d’1 m³ of wood with 1 meter logs”. But be careful, a stere of wood is not necessarily equivalent to 1 m3 wood would be too simple.
In reality, there is a subtlety: a stere is 1 m3 wood stacked in 1 meter logs, except that these logs can also be sold in the “50 cm, 33 cm or 25 cm” format, explains the boss of the Pechavy energy distribution group.
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Also, you have to pay close attention to the size of the logs. Here are the equivalences according to their size:
- 1 stere in logs of 1 m ≈ 1 m3
- 1 stere in logs of 50 cm ≈ 0.80 m³
- 1 cubic meter in logs of 33 cm ≈ 0.70 m³
- 1 stere in logs of 25 cm ≈ 0.60 m³
The most used unit is now the cubic meter
The most commonly used log length is 50 cm, size which allows good power heating, notes Frédéric Pechavy. 25 cm and 33 cm logs are often recommended for small inserts.
However, the demand for shorter logs (33 cm or even 25 cm) is increasing, in particular due to more compact fireplaces and modern homes, generally better insulated and requiring less heating power.
Wood rope, on the other hand, is “an old unit of measurement for the volume of firewood”. It often corresponds to three steres.
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It was replaced by the cubic meter, which has now become the official unit. So a rope is worth between 1.80 and 3 m3.
How to buy the right wood?
How much does it cost to buy wood? The price varies depending on the type of wood (drying wood, dry wood, parboiled logs, densified logs), the species and its department. According to the site JF Wood energy, the price of a stere varies between 89 and 115 euros depending on the region.
An increasing price for this year 2025.
After several years of stability, prices are slightly increasing. This development is explained in particular by the increase in operating costs (equipment, fuel, transport, etc.).
It is therefore useful to know where to turn to stock up:
- For damp wood, FF3C recommends purchasing directly from forest operators.
- For dry wood, densified logs or even parboiled logs, the Federation recommends going to specialized distributors in order to obtain good quality wood.
In addition to these purchasing recommendations, ADEME provides advice to limit the emission of pollutants. Dry wood must be burned with split, untreated logs.
All you have to do is sweep the chimney, an operation recommended once a year, before the start of the heating season.