How to Season Firewood

Seasoned firewood for wood boilers refers to wood that's been cut, split, and dried long enough to reduce its moisture content to a level that burns efficiently and cleanly — typically 20% moisture or less. Properly seasoned firewood burns hotter, produces less smoke and creosote, ignites more easily, and helps extend the life of your chimney by reducing the risk of chimney fires.

Seasoning time depends on wood type, climate, and storage conditions, but generally takes 6 to 12 months — denser hardwoods can take longer. Wood cut and split early in the year and dried through the warm summer months is typically ready by the following winter. A moisture meter is the most reliable way to check; seasoned wood should also look dry and brittle, with cracks on the ends, and make a sharp, resonant sound when two pieces are banged together.

Best Practices for Seasoning Firewood

• Cut to the right length — typically 16" or less; check your boiler's specifications.
• Split it — splitting exposes more surface area to air and speeds drying. Aim for pieces no larger than 6" in diameter.
• Stack for airflow — alternate layers with space between logs, and keep the stack off the ground on a raised platform or pallet.
• Choose a sunny, windy spot — sun and wind speed up drying. A tarp or cover over the sides that blocks wind or sun slows the process — leave the sides open.
• Cover only the top of the stack with a tarp or waterproof cover to keep rain and snow off while still allowing airflow.
• Give it time — 6 to 12 months, checked with a moisture meter, targeting 20% or less.
• Test before burning — check moisture and listen for that sharp, resonant knock.
• Use the oldest wood first so newer, less-seasoned wood keeps drying until it's ready.

For handling, placing the firewood stack near the boiler makes loading quicker and easier. Storing wood in an empty 275- or 330-gallon metal tote cage also makes for easy transport with a tractor and forks.

Burning unseasoned or improperly seasoned firewood causes smoldering, incomplete combustion, and increased smoke, pollutants, and creosote — so it's worth the wait to season it properly.