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If you use a wood stove or any other combustion device in your home, it’s crucial to ensure complete combustion.
In this blog post, we explain the difference between complete and incomplete combustion, the risks of incomplete combustion, and how to prevent it in your wood stove.

What is incomplete combustion?

In complete combustion, all the wood in your stove is efficiently converted into heat, releasing only water vapor and CO₂. The fuel then fully binds with the oxygen. However, in incomplete combustion, this process does not occur optimally. This can happen if there is too little oxygen, if the wood is too moist, or if the stove is not burning at the right temperature. In this case, the fuel does not fully bind with the oxygen. This results in smoke and the release of harmful substances, such as carbon monoxide (CO), fine particles, and tar. These substances can be harmful not only to your health but also to the environment.

The combustion in a wood stove is represented by the following chemical reaction equations:

Complete combustion in a wood stove: C₆H₁₀O₅ + 6O₂ → 6CO₂ + 5H₂O

Incomplete combustion in a wood stove: m C₆H₁₀O₅ + 3O₂ → 3CO + 3C + 5H₂O

Risks of incomplete combustion

One of the biggest risks of incomplete combustion is the formation of carbon monoxide (CO). This is a colorless and odorless gas that can cause serious health problems when inhaled. Symptoms of carbon monoxide poisoning range from headaches and dizziness to unconsciousness and, in extreme cases, death. Poorly ventilated spaces are particularly at risk.

Additionally, incomplete combustion leads to the buildup of tar and soot in the flue. This increases the risk of a chimney fire.

Recognizing incomplete combustion

You can recognize incomplete combustion in your stove in the following ways:

• The flames are unstable and somewhat orange and yellow.
• Gray or black smoke comes from your chimney.

Preventing incomplete combustion

For complete combustion in your wood stove, we have the following recommendations.

• Ensure sufficient oxygen. A wood stove requires adequate airflow to guarantee complete combustion. Make sure the air inlet of your stove functions properly.
• Use dry wood. Burning moist wood is one of the main causes of incomplete combustion. Ensure that your wood is well dried and has a moisture content of less than 20%. Dry wood provides cleaner and more efficient combustion. Burning moist wood can also lead to creosote formation, which further increases the risk of a chimney fire.
• Burn at the right temperature. A temperature that is too low results in incomplete combustion. It is important to light your wood stove properly and ensure it burns hot enough before adding more wood.
• Regular maintenance. Regular maintenance of your wood stove and flue is essential for safe operation. Have your chimney swept at least once a year and check that all parts of your stove function properly.
• Choose a wood stove with the right capacity. A stove with too much power for the space may smolder, leading to incomplete combustion.

At Leenders Haardkachels, we value safety and efficiency. Our modern wood stoves are designed for efficient and safe combustion. Each stove in our collection has its own story and fire.