Today, the choice of energy source is no longer a question of comfort and romance, but has primarily become a question of money. Skyrocketing energy costs are fuelling the desire for independence from resources. This is why a raw material that is practically on our doorstep is coming into focus: Wood is currently the alternative to oil and gas when it comes to heating. And rightly so, as it has an incomparably positive ecological balance. Provided it is utilised highly effectively and burnt almost residue-free, for example in a storage heating stove.
RAW MATERIAL WOOD
Alongside the direct use of solar energy, heating with wood is the most environmentally friendly form of heat generation. Only as much CO 2 is added to the atmosphere as the wood, or the tree that is burnt, has absorbed in its lifetime. A healthy cycle is created. The prerequisite, however, is optimum efficiency when burning and the utilisation of dry, seasoned wood.
THE NATURAL CYCLE
- Heating in harmony with nature
- Wood is stored solar energy
- Wood is constantly growing back – on our doorstep
- Outstanding ecological balance due to natural cycle
CALORIFIC VALUES OF AIR-DRY WOOD (WOOD MOISTURE CONTENT APPROX. 15 %)
The calorific value is reduced by the water content of the wood. A low water content is not only important for good combustion, but also for the energy output and therefore for your wallet. In terms of calorific value, one cubic metre of air-dried hardwood (approx. 450 kg) is equivalent to around 210 litres of heating oil. In terms of weight, for example, 1 kg of logs can replace 0.4 litres of heating oil. 1 litre of heating oil is equivalent to 1 m³ of gas. Source: Ed. Holzabsatzfonds, Naturally wood – future-proof heating.
| Tree species | Calorific value per kg in kWh |
| Hornbeam | 4,0 |
| European beech | 4,0 |
| Oak | 4,2 |
| Robinia | 4,1 |
| Birch tree | 4,3 |
| Maple tree | 4,1 |
| Alder tree | 4,1 |
| Willow | 4,1 |
| Poplar tree | 4,1 |
| Pine tree | 4,4 |
| Larch tree | 4,3 |
| Spruce wood | 4,5 |
| Fir tree | 4,5 |
STORING DRY WOOD CORRECTLY
If you follow a few basic principles when storing firewood, you will achieve the optimum calorific value when it burns and reduce the impact on the environment.
You should pay attention to this when storing wood:
- Small pieces of wood dry faster than pieces by the metre. It is best to cut them to the right length straight away (they will dry faster) and store them. Stacking crosswise has proven effective for ventilation.
- The wood pile must be well ventilated. The bottom layers should be at least 20 cm from the floor. A gap of 8 cm should be left behind the wood pile so that air can circulate freely around the pile.
- A roof protects the wood pile from rain – BUT: do not wrap the wood in plastic!
- A cellar or garage are not suitable for storing wood, as the lack of draught may cause mould.
DAMAGE CAUSED BY DAMP WOOD
Wood that has been poorly stored or is still too „green“ contains a lot of water. Burning such wood in the stove can result in expensive consequential damage. The water must first be „boiled out“ before the wood burns. This results in a lower calorific value, as a lot of energy is used to „dry“ the wood. Much worse, however, is that the temperature in the combustion chamber is lowered. The wood components can no longer be completely burnt. The unburnt wood gases are released into the environment through the chimney or settle as tar and soot on the stove walls and in the chimney. This soiling of the flue gas flues and the chimney prevents optimum heat emission from the heating surfaces, as they are virtually „insulated“ by soot and tar. In other words, well-seasoned wood does not smoke, heats well, does not soot up the stove and has a much lower impact on the environment.
