Chimney Safety Institute of America (CSIA) Certification Practice Test

What is the result of having too much moisture in wood when burned?

1. Higher combustion efficiency

2. More smoke and lower BTUs

3. Reduced flue gas temperature

4. Increased creosote buildup

The correct answer is: More smoke and lower BTUs

When wood with excessive moisture is burned, the result is indeed more smoke and lower BTUs (British Thermal Units). This occurs because water content in the wood requires energy to evaporate before the wood can combust effectively. As a result, much of the heat produced during burning goes into evaporating the moisture rather than generating heat for energy use. This incomplete combustion results in the production of smoke, which is composed of unburned particles and gases. Furthermore, the lower BTUs indicate that the energy output of the fire is reduced, making it less efficient for heating purposes. In contrast, properly seasoned wood, which has lower moisture content, burns hotter and cleaner, providing better heat output and reduced emissions. This understanding is essential for anyone looking to optimize their wood-burning practices. The reduction in efficiency associated with burning wet wood not only impacts heat performance but can also lead to other issues, such as increased creosote buildup in flues due to incomplete combustion of the volatile compounds released in the smoke.