Quick Answer
When choosing wood for burning, consider the wood's moisture content, density, and BTU value to ensure efficient and clean combustion. Look for hardwoods and softwoods with low moisture content and high BTU value. Opt for woods with fewer knots and branches.
Moisture Content Considerations
Moisture content is critical when selecting wood for burning, particularly for outdoor wood boilers. Aim for wood with a moisture content between 15% and 20% for optimal combustion. Wood with more than 25% moisture content can lead to incomplete combustion, resulting in reduced efficiency and increased emissions. Use a wood moisture meter to ensure accurate readings.
Wood Density and BTU Value
Hardwoods generally have a higher BTU value than softwoods, making them a more efficient choice for burning. Oak, maple, and ash are popular hardwood options, while fir, spruce, and pine are common softwoods. Look for woods with a BTU value of at least 20 million BTU per cord. Density is also a factor, with denser woods burning more slowly and producing less ash.
Knots and Branches
Knots and branches can disrupt the combustion process, reducing efficiency and increasing emissions. Opt for woods with fewer knots and branches, as they burn more cleanly and consistently. Use a chainsaw or pruning saw to remove knots and branches before burning, or choose woods that are already processed and ready for use.
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