The Core Difference
Seasoned firewood is wood that's been cut, split, stacked, and left to air-dry until its moisture content drops to around 20 percent or lower. Kiln-dried firewood goes through the same cutting and splitting, then spends time in a heated kiln instead of a stack outdoors, bringing moisture down to roughly 8 to 12 percent in a matter of days.
Both are "dry" firewood in the sense that they'll burn well. The differences are in moisture level, cost, and what the drying process does or doesn't kill.
Moisture Content, Side by Side
- Green (freshly cut) wood: 45 to 60 percent moisture
- Properly seasoned wood: 20 percent or below
- Kiln-dried wood: 8 to 12 percent, sometimes as low as 6 percent
That gap matters. Wood above 20 percent moisture burns cooler, produces more smoke, and builds up more creosote in a chimney or stovepipe. Kiln-dried wood, being drier still, lights faster and burns hotter right out of the bag — useful for a quick fire, less necessary for an all-night burn in a wood stove.
How Long Seasoning Actually Takes
Seasoning time depends on species and how the wood is stacked. Split, stacked in a single row, off the ground, and exposed to sun and wind:
- Softwoods (pine, spruce, fir): 6 to 12 months
- Ash, birch, soft maple: 8 to 12 months
- Oak, hickory, other dense hardwoods: 12 to 24 months
Wood that's stacked whole (unsplit) or piled in a shaded, damp spot can take twice as long, or never fully season at all.
What Kiln-Drying Adds That Seasoning Doesn't
A kiln heats wood to a sustained temperature, typically well above 140°F, for enough hours to drive out moisture and also kill insect eggs, larvae, and fungal spores living in the bark and wood. That's why kiln-dried firewood is the only category widely accepted for interstate transport and campground sales without a local-quarantine exception — it comes with a reduced risk of carrying invasive pests like emerald ash borer.
Seasoning alone doesn't reliably kill pests. Air-drying reduces moisture, but insects can survive in dry bark for a long time.
Cost and Availability
Kiln-dried firewood costs more — often noticeably more per cord — because of the fuel, equipment, and time to run a kiln, plus the lower yield from moisture loss. Seasoned firewood is usually cheaper, especially if you buy from a supplier who buys wood green and stacks it themselves months ahead of your order.
Which One Should You Buy?
Buy kiln-dried if:
- You need firewood right away and can't wait out a seasoning season
- You're transporting wood any real distance, including to a state or region with an active pest quarantine
- You want the driest, most consistent burn for an indoor wood stove or fireplace insert
Buy seasoned (properly, air-dried) if:
- You're buying locally, close to where you'll burn it
- You have storage space to buy ahead and let a supplier's already-seasoned stock finish drying if needed
- Cost matters more than moisture precision, and 15-20 percent moisture is good enough for your setup
How to Check What You're Actually Getting
Ask the seller for a moisture reading, or check it yourself with a $15-$20 pin-type moisture meter — split a piece open and test the freshly exposed face, not the outer bark, which reads dry even on green wood. Anything above 20 percent isn't seasoned yet, whatever the seller calls it.
Check firewood delivery availability in your area or find a local supplier in our free directory who can tell you exactly how their wood was dried.