- One ster is one stacked cubic meter: a pile of logs 1 m wide, 1 m high and 1 m deep, with the air between the logs included.
- It holds only about 0.6 to 0.7 m³ of solid wood (a solid cubic meter).
- With us, a ster of dry beech weighs about 450 kg and a ster of birch about 420 kg. Softwood is lighter.
- Our wood finder suggests 1 ster for a fireplace that burns regularly and 2 ster for a wood stove.
In this article
A ster of firewood is one stacked cubic meter: a pile of logs 1 meter wide, 1 meter high and 1 meter deep, including the air between the logs. It holds only about 0.6 to 0.7 cubic meters of solid wood and weighs about 450 kilograms in dry beech.
If you buy firewood in Switzerland, you will see the word «Ster» everywhere: at forestry offices, on farms and in online shops. In English it is called a stere, in German «Raummeter». So what is a ster of firewood? It is a measure of volume, not a single piece of wood. Once you know the unit, you can compare offers properly and order neither too little nor too much.
What is a ster of firewood? The units at a glance
Ster and «Raummeter» (rm) mean the same thing. In the Swiss firewood trade, «Ster» is the more common word. Two other units are easy to mix up with it:
| Unit | What it means | Equals |
|---|---|---|
| Ster / stacked cubic meter (rm) | 1 m³ of stacked logs, air between the logs included | about 0.6 to 0.7 solid cubic meters |
| Solid cubic meter (fm, «Festmeter») | 1 m³ of pure wood, no gaps | about 1.4 to 1.6 ster |
| Loose cubic meter (srm, «Schüttraummeter») | 1 m³ of logs tipped loosely into a pile | about 0.65 ster |
Sources: WSL, «Solare Trocknung von Scheitholz» (1 solid cubic meter = 1.6 ster for 33 cm logs, 2.4 to 2.5 loose cubic meters); Swiss Federal Office for the Environment (BAFU), Grundlagen Monitoring Holzenergie in der Schweiz (1 ster = 0.7 m³). Values vary slightly with log length and stacking.
The difference between a ster and a loose cubic meter is bigger than it sounds: with a loose cubic meter you get about a third less wood than with a ster. When you compare offers, always ask which unit is meant.
How much wood is in a ster?
A ster is a stack, not a heap: 1 m wide, 1 m high and 1 m deep. With 33 cm logs that is three rows behind each other. Because logs never fit together without gaps, the stack holds less than one cubic meter of solid wood. BAFU uses 0.7 m³ per ster, WSL a little over 0.6. The rest is air.
That is also why stacked wood is so easy to check. You see what you get and can measure the stack. With wood tipped loosely, you cannot.
What does a ster of wood weigh?
The weight depends on the wood species and on moisture. For our dry wood (under 18% moisture), 1 ster weighs:
| Wood species | Weight per ster (dry) |
|---|---|
| Beech | about 450 kg |
| Birch | about 420 kg |
Softwood is lighter than hardwood because it is less dense. For our 33 cm beech firewood we state 1 ster as about 450 kg. Fresh, wet wood is much heavier. If your ster weighs noticeably more than these values, the wood may still be too moist. How to dry and store firewood properly is covered in How to store and stack firewood.
How much heat is in a ster?
A ster of beech with 20% water content gives about 1,900 kilowatt hours of heat, a ster of spruce about 1,300 (Holzenergie Schweiz on behalf of BAFU). Hardwoods such as beech deliver more energy per ster than softwoods because they are denser.
Source: Holzenergie Schweiz on behalf of BAFU, Grundlagen Monitoring Holzenergie in der Schweiz (2023), table A9: beech 1,887 kWh, spruce 1,334 kWh per ster at 20% water content.
For comparison: according to EnergieSchweiz, 5 to 6 ster of hardwood replace about 1,000 liters of heating oil.
How much wood do you need?
That depends on how often and with what you heat. Our wood finder gives you guide values:
| You heat with | Guide value |
|---|---|
| A fireplace that burns regularly | 1 ster |
| A wood stove that runs regularly | 2 ster |
If you want to heat a whole house with wood, it is best to calculate from your previous consumption: 1,000 liters of heating oil equal 5 to 6 ster of hardwood. The wood finder gives you the right amount in three questions, and if you are unsure, we are happy to work it out with you. How to plan your supply for the cold season is explained in Firewood for winter.
How to check that you really get a ster
- Clarify the unit: ster (stacked cubic meter), loose cubic meter or kilograms? Only ster and stacked cubic meters are directly comparable.
- Clarify the log length: 25, 33 or 50 cm. It has to fit your stove. We offer beech firewood in 33 cm and beech firewood in 25 cm.
- Measure it: 1 m wide, 1 m high, 1 m deep. With a stacked delivery you can check this right at the pile.
- Ask about moisture: oven-ready wood has under 20% moisture (Holzenergie Schweiz). We deliver ours at under 18%.
- Compare the total price: delivery and stacking cost extra with many suppliers. What a ster costs and what is included is explained in Firewood prices in Switzerland.
Frequently asked questions about the ster
What does a ster of wood cost?
For dry, oven-ready beech (33 cm), the Swiss Farmers' Union currently recommends 180 to 220 francs per ster, without delivery. With us, a ster of stacked beech costs CHF 329.00, including delivery and stacking. All details are in Firewood prices in Switzerland.
How many ster are in 1 solid cubic meter of wood?
About 1.4 to 1.6 ster. WSL uses 1.6 ster per solid cubic meter for 33 cm logs, BAFU 0.7 solid cubic meters per ster (about 1.4 ster).
How many ster is a Klafter?
Klafter is an old measure that was defined differently from region to region. Today it is often taken to mean 3 ster. Ask the supplier which quantity is meant.
Is a ster the same as a cubic meter?
Almost. A ster is a cubic meter of stacked wood, so it includes the air between the logs. Pure wood is only about 0.7 m³. A solid cubic meter, on the other hand, is a cubic meter of pure wood.
How many kWh are in a ster of wood?
A ster of beech with 20% water content gives about 1,900 kWh, a ster of spruce about 1,300 kWh. Hardwoods hold more energy per ster than softwoods.
How many ster does a single-family house need?
That depends on the building and the heating. Calculate from your previous consumption: 1,000 liters of heating oil equal 5 to 6 ster of hardwood (EnergieSchweiz). If you are unsure, write to us and we will work out the amount with you.
In short: a ster is a stack, not a heap
A ster of wood is one cubic meter of stacked logs, holds about 0.7 cubic meters of solid wood and weighs about 450 kilograms in beech. When you compare offers, look at the unit, the log length and the moisture, and you will order the right amount for your stove. With us you can order firewood stacked and delivered: you see what you get. You will find more answers in Firewood in Switzerland: questions and answers.
Send us a short message and we will work out the amount with you, before you order.
