About the importance of wood moisture content

As winter approaches, our reliance on wood-fired boilers and stoves increases, making it crucial to use heating material that is both efficient and environmentally friendly. To achieve this goal, it is essential to burn high-quality wood with low moisture content. To inform potters, dealers, and customers about the importance of wood moisture content and its impact on equipment efficiency, we have compiled essential information about the moisture content in various heating materials.

What is moisture content?

Moisture content refers to one of the key parameters used in the classification of wood for heating purposes, as it directly impacts the heating value of wood. It is defined as the ratio of water present in a piece of wood to the weight of the wood itself. As water does not burn, the higher the moisture content in wood, the more challenging it becomes to burn efficiently. Therefore, moisture content is a critical factor to consider when evaluating the quality and suitability of wood for various heating applications.

How does moisture content affect combustion and heating efficiency?

Moisture content significantly affects combustion and heating efficiency. When burning wood with high moisture content, the water in the wood must first be evaporated. This process consumes energy and reduces the amount of heat energy released during combustion. As a result, heating devices not specifically designed for burning wet wood may take longer to heat up and might not reach their rated output at all. Additionally, the heat produced by burning wet wood is mostly wasted as it evaporates into hot steam, making it inefficient for home heating purposes. Using logs with insufficiently low moisture levels during combustion can lead to warping, excessive smoke, and soot emission. Moreover, if left unattended, burning damp wood can cause chimney fires and necessitate more frequent chimney cleaning.

For optimal heating efficiency, it is recommended to use wood with a moisture content of less than 20%. Such wood is over 2 times more efficient than wood with a moisture content of 45%. As the humidity level decreases, the heating efficiency of wood increases, resulting in longer and more efficient burning. This means that less heating material is needed to produce the same amount of heat.

What is the ideal humidity level for my heater?

The ideal humidity level for your heater depends on the type of heating device you are using. It’s essential to consider the moisture content of the heating material, which is influenced by factors such as the type of wood, log size, and storage conditions. Freshly felled trees typically have a moisture level of 45-60%, but with natural storage, this can be reduced to 25% within 6-18 months. To store wood properly, it’s best to keep it covered in a well-ventilated area. Different heating devices require varying wood moisture levels for efficient combustion. Industrial equipment and boilers can handle material with a moisture level of up to 45%. However, for domestic stoves and fireplaces, it is recommended to keep the humidity level of the wood below 20% for optimal performance. Therefore, the appropriate humidity level for your heater depends on its type; for industrial equipment, up to 45% is acceptable, while for domestic stoves and fireplaces, it should remain below 20%. Properly seasoned wood with lower moisture content will generally provide better heat output and efficiency.

Tips for the best storage of wood.

Cut the material to size before drying. To dry, place the trees in a sunny location with good air circulation for 1 or 2 summers, ensuring they are not exposed to rain or snow. Stack the trees during early spring for use in the following winter. Large cracks and easily removable chips are signs that the wood has dried well.