How To season Firewood

April 16, 2023

Lets go over the benefits and steps to season firewood for your outdoor wood boiler to get the best efficiency.

Seasoned firewood for wood boilers typically refers to wood that has been cut, split, and allowed to dry for a sufficient period of time to reduce its moisture content to a level that is optimal for efficient and clean burning. The moisture content of seasoned firewood is typically around 20% or less, although some sources may define seasoned firewood as having a moisture content of 25% or lower.

The process of seasoning firewood for your boiler involves allowing the wood to dry out, which helps to reduce its moisture content and improve its combustion properties. Properly seasoned firewood burns hotter and produces less smoke and creosote, which can build up in chimneys and create a fire hazard. Additionally, seasoned firewood ignites more easily and produces less creosote, which can help extend the lifespan of your chimney and reduce the risk of chimney fires.

The time required to season firewood depends on various factors, including the type of wood, the climate, and the storage conditions. In general, it takes approximately 6 to 12 months for firewood to properly season, although some denser hardwoods may take longer. Wood that has been cut and split early in the year and allowed to dry during the warm and dry summer months is typically ready to be burned by the following winter.

To determine if firewood is seasoned, you can use a moisture meter to measure the moisture content of the wood. A moisture content of 20% or less is generally considered suitable for seasoned firewood. Additionally, seasoned firewood should have a dry and brittle appearance, with cracks or splits on the ends, and it should make a sharp, resonant sound when banged together.

Here are some best practices for seasoning firewood for your wood boiler:

  1. Cut firewood to the right length: Firewood should be cut to the appropriate length for your fireplace or wood stove. Typically, firewood should be cut to a length of 16 inches or less for most residential wood stoves or fireplaces. Check the specifications of your wood-burning appliance for the recommended length.
  2. Split firewood: Splitting firewood exposes more surface area to air and helps the wood dry faster. Use a log splitter, axe, or maul to split the firewood into smaller pieces, ideally no larger than 6 inches in diameter.
  3. Stack firewood properly: Stack firewood in a way that promotes good airflow. Create a stack with alternating layers of firewood, leaving space between the logs for air circulation. Stack the firewood off the ground, on a raised platform or pallet, to prevent moisture from being absorbed from the ground.
  4. Choose a sunny and windy location: Place the firewood stack in a sunny and well-ventilated area. Sunlight and wind can help accelerate the drying process by evaporating moisture from the wood. Having a tarp or metal over the top of the wood pile that prevents free flow of wind or blocks sun can slow down the drying process. Best to leave the wood without a covering.
  5. Cover the top of the stack: Cover the top of the firewood stack with a tarp or waterproof cover to protect it from rain and snow while still allowing airflow. Avoid covering the sides of the stack as this can trap moisture and impede the drying process.
  6. Allow time for seasoning: Firewood typically takes 6 to 12 months to properly season, depending on the type of wood, climate, and other factors. Check the moisture content of the firewood with a moisture meter, and aim for a moisture content of 20% or less before using it as firewood.
  7. Test the firewood: Once the firewood is seasoned, test it by checking the moisture content and by banging two pieces together. Well-seasoned firewood should have a moisture content of 20% or less, and it should make a sharp, resonant sound when banged together.
  8. Use the oldest firewood first: To ensure that your firewood is properly seasoned, use the oldest firewood first. This allows the newer, less seasoned wood to continue drying until it's ready to be burned.

There are some options on handling and storing firewood to help get it ready for your outdoor wood boiler. Consider placing the firewood stack near the boiler for quicker and easier loading. Storing wood in an empty 275 gallon or 330 gallon metal tote cage makes for easier transport for a tractor with forks.

It's important to note that burning unseasoned or improperly seasoned firewood can result in less efficient and less environmentally friendly fires, as the excess moisture in the wood can cause smoldering, incomplete combustion, and increased emissions of smoke, pollutants, and creosote. Therefore, it's recommended to properly season firewood before using it for burning to ensure optimal performance and safety.