Seasoning & Moisture: The Difference Between Wood That Burns and Wood That Struggles
Firewood needs time, airflow and the right storage conditions to dry properly. Learn what moisture percentages mean, how to test firewood correctly and what to ask a supplier before you order.
Dry wood burns cleaner and more efficiently.
For a practical home-burning target, moisture readings around 15–20% on the freshly split interior face are commonly recommended.
Wet firewood makes your fire work harder
Before wet wood can burn efficiently, energy has to be used to heat and evaporate the water inside it. That can mean harder starts, lower firebox temperatures, more visible smoke and less useful heat in the room.
Dry wood starts more easily
When less energy is spent evaporating water, a fire can establish itself faster and reach a cleaner-burning temperature sooner.
More energy reaches the room
Moisture is extra weight that does not provide heat. Drier fuel lets more of the wood’s energy contribute to combustion and useful heating.
Cool, smoky fires are undesirable
Incomplete, low-temperature combustion can increase smoke and contribute to unwanted deposits in the chimney or flue system.
Green, seasoned and kiln-dried are not the same thing
These terms describe how firewood has been handled, but the actual moisture reading is more useful than the label alone.
Recently harvested wood
Freshly cut wood can contain a large amount of water and normally needs substantial drying time before it performs well as heating fuel.
Dried naturally over time
“Seasoned” does not guarantee one exact moisture percentage. Ask when it was split, how it was stacked and whether the supplier checks moisture.
Dried with added heat
Kiln drying can reduce moisture more quickly and consistently, but storage after drying still matters. Wood can absorb moisture again if poorly stored.
Test the inside of the wood—not just the dry-looking surface
A basic pin-style moisture meter is one of the easiest ways to check whether firewood is ready to burn.
How to get a useful reading
Testing several pieces gives you a better picture of the load than checking one convenient log.
- Choose several representative pieces from different parts of the stack.
- Bring a piece to roughly room temperature if practical; very cold wood can affect some meters.
- Split the piece again to expose a fresh interior face.
- Push the meter pins into the newly exposed face, ideally across the grain if your meter instructions recommend it.
- Test more than one spot and more than one piece. Look for the pattern, not one perfect number.
Four things help firewood dry
There is no universal “six months” or “one year” rule. Drying time changes with species, climate, log size, when it was split and how the stack is exposed.
A good stack keeps drying after delivery
Firewood should be protected from prolonged wetting without trapping moisture around the stack.
✓ Better storage habits
- Keep the wood off soil and standing water.
- Choose a location with good airflow.
- Cover the top of the stack from rain and snow while leaving the sides open where practical.
- Stack loosely enough for air to move between pieces.
- Rotate older wood forward so it gets burned first.
- Keep only a limited amount indoors near the appliance and follow fire-safety clearances.
× Common drying mistakes
- Wrapping the entire pile tightly in an impermeable tarp.
- Stacking directly on wet ground.
- Leaving large rounds unsplit and expecting them to dry quickly.
- Putting freshly cut wood into a closed shed with little ventilation.
- Assuming wood is dry because the ends are cracked or the bark is loose.
- Bringing a large quantity of wet firewood inside the home to “finish drying.”
Questions worth asking the supplier
Good suppliers should be able to explain their process clearly, even if they do not promise an exact moisture percentage for every piece.
| Question | Why it helps | What you learn |
|---|---|---|
| When was the wood split? | Split wood normally dries much faster than rounds. | Whether the drying clock really started months ago. |
| How has it been stored? | Airflow and rain protection matter as much as elapsed time. | Whether “seasoned” means properly stacked or simply old. |
| Do you check moisture? | A meter can provide useful evidence when used correctly. | Whether the seller has a measurable drying standard. |
| Where is the reading taken? | Outside surfaces can be much drier than the centre. | Whether the measurement reflects the interior of the wood. |
| What species are included? | Species dry at different rates and have different densities. | Why some pieces in a mixed load may read differently. |
| Is it ready to burn now? | Some suppliers sell both green and seasoned inventory. | Whether you should burn it this season or store it longer. |
Further reading
Natural Resources Canada materials commonly describe dry stacked firewood around M20%, while the U.S. EPA’s historic Burn Wise guidance states that wood burns most efficiently around 15–20% moisture content. Health Canada also recommends reducing wood smoke exposure by burning properly seasoned wood and using good burning practices.
Natural Resources Canada → EPA Moisture Meter Guide → Health Canada Wood Smoke →Seasoning & moisture FAQ
What moisture content should firewood be before burning?
A practical target is around 15–20% moisture content when measured on the freshly split interior face. Treat the reading as part of the picture rather than an absolute guarantee of how every piece will burn.
How long does firewood take to season?
There is no single answer. Species, split size, local weather, sun, airflow and storage all matter. Some wood can dry within one favourable season, while dense species or large pieces may need much longer.
Can I tell firewood is dry just by looking at it?
Visual clues such as end checking, faded colour, loose bark and lighter weight can be useful, but none is as reliable as checking several freshly split pieces with a moisture meter.
Why do I have to split the log before testing moisture?
The exposed outside of a piece can dry faster than its centre. Splitting the wood immediately before testing gives the meter access to the interior moisture that matters most.
Is kiln-dried firewood always below 20%?
Not necessarily. Kiln drying describes a process, not one universal finished moisture specification. Ask the supplier about the target moisture and how the wood has been stored since drying.
Can seasoned firewood get wet again?
Yes. Rain can wet the surface, and poor long-term storage can allow wood to regain moisture. Well-seasoned wood should still be stored off the ground with airflow and appropriate weather protection.
Should I cover the entire firewood pile with a tarp?
Usually it is better to protect the top while preserving airflow around the sides. Completely wrapping a stack can trap humidity and slow drying if moisture cannot escape.
Can I dry wet firewood inside my house?
Bringing large quantities of wet firewood indoors can release significant moisture into the home and may also bring insects or debris inside. Store and season the bulk of your firewood outdoors in a suitable ventilated setup.
Find suppliers offering seasoned and kiln-dried firewood.
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