What Moisture Content Should Firewood Be?

When deciding what moisture content should firewood be, the target is 20 percent or less. Fresh wood holds significant water that robs heat and creates heavy smoke. Seasoned wood with 20 percent moisture or less catches easily, produces steady heat, and keeps wood stove flues cleaner.

FirewoodGearHQ earns a commission when you buy through links on our product pages, at no extra cost to you. Read our affiliate disclosure.

The quick answer: what moisture content should firewood be

Firewood is ready to burn when its moisture content drops to 20 percent or less. Fresh-cut green wood contains substantial water, often accounting for much of its total weight. When placed in a wood stove or fireplace, a fire must expend significant heat energy boiling that water into steam before producing usable warmth. Wood that retains excess moisture burns cool, smolders, produces dark smoke, and deposits unburned wood gases as creosote along chimney walls.

The EPA Burn Wise program advises burning seasoned firewood at 20 percent moisture or less to protect air quality and maximize heating efficiency. When fuel is properly seasoned, fires ignite promptly, establish vigorous draft quickly, and burn clean. Distributing warm air through your living space with a heat-powered wood stove fan helps circulate heat efficiently when burning properly dried firewood. For more hearth setup recommendations, browse our stove accessories guide.

Firewood moisture content chart

Moisture meters designed for wood and lumber measure moisture percentage to help determine whether logs are dry enough for clean burning. Understanding how stated meter ranges relate to firewood combustion ensures you interpret readings accurately.

Moisture Level	Moisture Range	Burning Characteristics	Stated Meter Reference
Very dry	0% to 14.8%	Catches instantly; burns quickly and clean; excellent for kindling	coczow (Low: ≤14.8%), RDINSCOS (0%)
Seasoned	14.9% to 20.4%	Optimal heating range per EPA Burn Wise (20% or less); steady heat and low smoke	coczow (Medium: 14.9%~20.4%)
Unseasoned / wet	≥20.5%	Difficult to ignite; smothers heat, produces smoke and flue creosote; requires further drying	coczow (High: ≥20.5%)

Meters measure across broad wood ranges depending on their sensor design. For example, Prexiso specifies a wood moisture range from 0% to 57%, XRCLIF covers wood from 0-55%, and coczow spans 2.0% – 40.0% on wood. In contrast, TRAKLUME lists a 0.0-100.0% scale designed for relative comparative measurements between spots rather than absolute moisture percentages.

Furthermore, manufacturer presets often reflect woodworking rather than firewood standards. For instance, Tavool presets lumber indicators as Low (5-12%), Medium (12-17%), and High (17-60%) to prevent warping in hardwood flooring and construction lumber. For firewood combustion, EPA Burn Wise advises burning wood at 20 percent moisture or less, meaning seasoned firewood spans across Tavool’s Medium band and into the lower portion of its High lumber range. Always evaluate firewood against the 20 percent threshold rather than construction lumber modes.

What makes firewood dry faster

Split rounds promptly

Bark functions as a moisture barrier designed to keep trees hydrated. Leaving whole logs unsplit traps moisture inside the wood fibers for extended periods. Splitting logs exposes the porous interior grain and end fibers to moving air, accelerating the evaporation of sap and water. Breaking large rounds apart with a splitting maul or splitting axe creates manageable pieces that lose moisture far quicker than intact logs.

Stack off wet soil

Ground contact draws dampness from the soil directly into the bottom row of your pile. Wet soil also attracts insects and accelerates fungal rot. Stacking your wood on wooden pallets or elevating it on a firewood rack with cover allows continuous airflow underneath the pile. Keep rows separated slightly so air flows between adjacent stacks.

Pick a sunny, windy location

Sunlight provides thermal energy that warms the wood, while wind whisks away evaporated moisture before it settles back into the woodpile. Place your stack in an open area that catches prevailing winds and direct sun exposure. Avoid tucked-away spots beneath heavy tree canopies or shaded exterior walls where stagnant damp air lingers.

Cover the top while leaving sides open

Rain and falling snow soak into exposed end grain. A sturdy metal roof or fitted top cover shields the pile from precipitation. Never wrap an entire woodpile down to the ground with an impermeable plastic tarp. Completely wrapped stacks trap ground humidity and sweat in warm weather, encouraging mold growth and delaying seasoning. Keep the sides open to let breezes pass through.

Allow adequate seasoning time

Drying wood to the target moisture level takes patience. Hardwoods like oak and hickory are dense and release internal water slowly, whereas softwoods dry faster. For species-specific drying guidelines, read our detailed guide on how long to season firewood, and review fuel choices in our guide to the best wood for a wood stove.

How to check firewood moisture content

Visual clues offer helpful hints, but using a dedicated moisture meter provides concrete verification before loading your stove.

• Pin meter measurement: Dual contact pins push into the wood fibers to read electrical resistance between the probes. The yowexa meter specifies inserting probes at least 3 mm into the material for accurate contact. Always split a log immediately before reading and press the pins firmly into the freshly exposed split face. Cut ends weather and dry prematurely, giving deceptively low readings compared to the log core.
• Pinless scanning considerations: Non-destructive meters use electromagnetic sensors to scan density beneath the surface without driving pins into the wood. TRAKLUME lists a pinless sensor depth of 0.79 inches, while GOYOJO lists depth detection up to 40mm. However, pinless sensors require a flat, uniform surface for flush contact, making them challenging to use on irregular, split firewood logs. Furthermore, models like TRAKLUME provide relative comparative values rather than absolute moisture percentages. For split cordwood, pin-type meters remain the standard tool; see our roundup of the best firewood moisture meters and our guide on how to use a firewood moisture meter.
• Radial cracks: Seasoned logs develop checking cracks that radiate outward from the center along the cut ends as moisture evaporates.
• Color and bark: Cut ends fade to a weathered gray or muted tone from sun and air exposure, while the freshly split interior remains clean. Bark may loosen on some wood species as internal moisture drops, though tight bark alone does not prove a piece is unseasoned.
• Sound and weight: Knocking seasoned splits together typically creates a sharp, resonant ringing sound, whereas wet logs produce a duller thud. Seasoned wood also feels noticeably lighter in the hand as water evaporates.

What happens if you burn it too soon

Burning firewood that exceeds 20 percent moisture creates operational and maintenance issues throughout your entire heating system. Damp wood smothers flame temperature because heat energy must evaporate trapped water before producing usable warmth. This reduces room heating and forces appliances to run inefficiently.

Cool firebox temperatures cause incomplete combustion, producing thick smoke laden with unburned particulates and acidic gases. As these vapors rise through a cold chimney flue, they condense along the liner walls into creosote. Creosote builds rapidly from unseasoned fuel, creating a serious chimney fire hazard and coating the stove viewing glass with dark soot. Monitoring firebox and flue temperatures with a stove thermometer helps you detect when cool burns indicate wet wood. Modern clean-burning heating appliances require properly seasoned firewood to deliver full performance; see our guide to the best wood stove for heating a house.

For safe wood stove operation, install heating appliances strictly according to manufacturer clearances and local building codes, maintain operational smoke and carbon monoxide alarms throughout the living space, schedule an annual chimney inspection by a qualified chimney professional, and burn seasoned wood only. Official safety recommendations from the CSIA, NFPA, and EPA Burn Wise emphasize that dry wood is the foundation of safe home heating.

Kiln-dried and store-bought wood

Packaged firewood offers a convenient alternative when homegrown seasoned cords are unavailable. Kiln-dried wood undergoes controlled heat cycles inside specialized kilns, lowering moisture content quickly and eradicating insects or mold spores.

Packaged bundles provide reliable fuel for hearths, campfires, and wood stoves. For example, Billy Buckskin packages an 18 lb seasoned juniper wood bundle that includes fatwood starter sticks for clean burning. Even when purchasing commercially bundled wood, inspect the package and verify the split face with a meter, because outdoor retail storage under rain or humidity can raise surface moisture above the 20 percent threshold.

Frequently Asked Questions

What moisture content should firewood be for immediate burning?

Firewood should be 20 percent moisture or less before you load it into a wood stove, fireplace, or fire pit. The EPA Burn Wise program advises staying at or below 20 percent to achieve clean combustion, produce maximum heat, and prevent creosote buildup.

Can firewood be too dry to burn safely in a wood stove?

Wood with very low moisture, such as kiln-dried pieces or dry wood that registers 0% on an RDINSCOS meter threshold, ignites rapidly and burns vigorously. While safe in balanced fuel loads, loading an entire firebox solely with extremely dry kindling can cause sudden heat spikes. Adjust air intake controls to maintain steady combustion when burning exceptionally dry fuel.

How does a pin moisture meter differ from a pinless moisture meter?

Pin meters utilize dual metal probes that penetrate the wood grain, such as the 3 mm probe insertion depth specified by yowexa. Pinless meters employ electromagnetic sensors to scan beneath the surface, such as the 0.79 inches depth specified by TRAKLUME or 40mm listed by GOYOJO. While pinless models avoid puncturing surfaces, they require flat material for flush contact and often read relative values, making pin meters more practical for rough split firewood.

Where is the best place on a log to check moisture content?

The best location to check moisture is the fresh split face of a split log. Cut ends dry much faster than the center of a log, which can produce misleadingly dry readings. Split the log open and immediately probe the center of the freshly exposed interior grain.

Why does burning wood above 20 percent moisture produce heavy smoke?

Wood above 20 percent moisture forces the fire to consume heat energy converting liquid water into steam. This drops firebox temperatures below the threshold required to burn volatile wood gases, releasing unburned hydrocarbons as thick smoke, soot, and chimney creosote.

How can you tell if firewood is dry without a moisture meter?

Seasoned wood often displays radial checking cracks across the cut ends, faded gray end grain, and feels lighter in weight than green wood. Knocking dry splits together typically produces a sharp, resonant sound rather than a dull thud. However, visual and physical signs can be deceptive; using a meter provides definitive confirmation.

Related guides

See our stove accessories hub, review top-rated instruments in our guide to the best firewood moisture meters, and learn measuring techniques in how to use a firewood moisture meter. To plan your woodpile, see how long to season firewood and choose the best wood for a wood stove. Improve heat circulation with the best wood stove fan and track flue heat with the best stove thermometer. Keep logs dry outdoors using a firewood rack with cover, split cordwood using a splitting maul or splitting axe, and review home hearth safety with our wood stove safety checklist. Also see our guides on can you bring firewood indoors, why does my wood stove glass turn black, and why does my wood stove smoke when I open the door.

About the author