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Dry Firewood: How to Season, Test and Store It
Wet wood burns cool and smoky, and the smoke condenses in the flue as creosote. Choosing and storing firewood is the single easiest way to keep a chimney cleaner between sweeps.
Why moisture matters to the chimney
Wood that still holds a lot of water spends much of its heat boiling that water off. The fire runs cooler, produces more smoke, and the cooler flue surfaces let that smoke condense into creosote. Creosote is the deposit that chimney sweeps remove and that fuels chimney fires. How the deposits form and progress is covered in our guide to creosote buildup and chimney cleaning.
The numbers to aim for
The U.S. EPA’s Burn Wise guidance says wood burns best at a moisture content of less than 20 percent, and that wood should be seasoned for at least six months. Seasoning time varies with species, how thickly the wood is split, and weather, so a calendar alone is not proof. A moisture reading is.
| Check | Seasoned wood | Green or wet wood |
|---|---|---|
| Moisture meter | Below 20 percent | Above 20 percent |
| Weight | Noticeably light for its size | Heavy |
| Sound | Hollow knock when two pieces are struck together | Dull thud |
| Color and ends | Darker, with cracks in the end grain | Bright, tight end grain |
| In the fire | Lights readily, little hissing | Hisses, smokes, burns sluggishly |
A pin-type moisture meter is inexpensive. Split a piece, then press the pins into the freshly exposed face, not the outer surface, and read it.
How to store firewood
- Outdoors, off the ground. Use a rack, pallet or rails so air moves under the stack and the bottom row does not wick up ground moisture.
- Cover only the top. EPA guidance is to cover the top and leave the sides open, because covering the sides traps moisture.
- Split it. Split faces dry far faster than whole rounds.
Do not shortcut this. Burning green wood hot to “dry it out” does not fix the condensation problem and tends to build deposits faster. If your fireplace has been smoky and the wood is fresh-cut, check the wood before suspecting the chimney.
Wood and chimney type
Seasoned hardwoods such as oak and maple are typically sold as long-burning, dense firewood. Softer woods burn faster. Either can be a clean fuel when dry. The deciding factor for creosote is moisture and combustion, not species. Pair any firewood choice with sound airflow: if you see smoke spilling into the room, see smoke problems and poor draft.
What dry wood does not fix
Dry wood reduces deposits but does not replace inspection. Cracked liners, failed crowns and blocked flues can exist with a perfect woodpile. If it has been a year or more since the last check, the schedule is in how often to inspect and clean a chimney.
Frequently asked questions
Can I burn wood the same year it is cut?
Only if it has actually reached low moisture. Freshly cut wood is typically far above 20 percent. The EPA’s six months is a minimum, and thick pieces, damp climates and shaded stacks can take longer. Test it.
Is kiln-dried firewood better?
Kiln-dried wood starts at a controlled low moisture, which makes it reliable, but it can still pick up moisture if stored uncovered or on the ground. Store it the same way.
Does a tarp over the whole stack help?
Not if it wraps the sides. A tarp that traps humidity can keep wood wet. Cover the top only and leave the sides open to air.
Can wet wood really damage the chimney?
Wet wood increases creosote and soot, which are the deposits behind most chimney fires.
Need the chimney checked?
If wood has been burned wet, or you are not sure what is in the flue, a chimney inspection will show it, and chimney cleaning removes the deposits. You can request a visit or call (862) 225-6529.
Sources
- U.S. EPA Burn Wise: Best Wood Burning Practices (moisture under 20 percent, at least six months of seasoning, store off the ground with only the top covered, moisture meter)
- Chimney Safety Institute of America (creosote and annual inspection guidance)