Firewood Guide: Choosing, Seasoning, Storing and Buying Wood That Keeps Your Chimney Clean

When wood burns, water must boil off before the wood itself can reach full combustion temperatures. Wet wood spends much of its energy drying itself, producing a cooler, smokier fire. CSIA lists unseasoned wood, restricted air supply and cooler-than-normal chimney temperatures as the conditions that speed creosote buildup. The smoke condenses on cool flue walls as creosote, the flammable residue behind most chimney fires. NFPA research found that failure to clean, a factor often seen in chimney fires, was the leading factor contributing to home heating fires. Dry wood burned hot does not eliminate creosote, but it slows it dramatically. See creosote and chimney fires.

Green wood is also heavy: seasoned wood typically has 20% or less moisture, and green wood may weigh 70 to 100 percent more than seasoned wood because of its water content (Wikipedia, Firewood). That is water you are paying to haul, stack and then boil off in your stove.

1. Dense hardwoods

Definition: Heavy, slow-growing broadleaf species such as hickory, white and red oak, sugar (hard) maple, beech, white ash, black locust and hophornbeam (ironwood). How to identify: Heavy for its size when dry, tight grain, thick or deeply furrowed bark on oak and hickory, smooth gray bark on beech. Oak splits show pronounced rays; ash splits cleanly and has a diamond-patterned bark. Typical heat value: About 22 to 28 million BTU per cord (Engineering ToolBox table). Typical cost: Usually the most expensive delivered wood in a market; estimated $250–$500 per seasoned cord in many US areas, higher in high-cost metros (estimate based on typical regional pricing; check local sellers). When it applies: Best choice for overnight burns and primary heat in stoves and inserts. Needs the longest drying time; oak commonly needs well over a year.

2. Medium-density hardwoods

Definition: Species such as soft (red) maple, cherry, black walnut, elm, sycamore, hackberry, paper and yellow birch. How to identify: Moderate weight; cherry has reddish heartwood and a pleasant smell; birch has papery bark that holds moisture if left on unsplit rounds. Typical heat value: About 18 to 24 million BTU per cord. Typical cost: Often sold as "mixed hardwood" at a small discount to oak and hickory. When it applies: Good all-round fireplace and shoulder-season wood; dries faster than oak.

3. Light hardwoods

Definition: Low-density broadleaf species such as cottonwood, aspen, basswood, willow, yellow-poplar and boxelder. How to identify: Light when dry, soft enough to dent with a thumbnail when green, very wet when freshly cut. Typical heat value: About 13 to 18 million BTU per cord. Typical cost: Cheapest hardwood; sometimes free from tree removals. When it applies: Kindling, quick fires in mild weather. University of Missouri Extension rates aspen and boxelder "poor" and cottonwood, basswood, yellow-poplar and willow "fair; suitable for kindling."

4. Resinous softwoods

Definition: Conifers with high pitch content, such as southern yellow pine, pinyon pine and some Douglas-fir and larch. How to identify: Sticky sap, strong turpentine smell, amber pitch pockets. Typical heat value: Varies widely; dense resinous pines can rival hardwoods per cord (Engineering ToolBox lists pinyon at 33.5 and Douglas-fir at 26.4 million BTU per cord). When it applies: Common, and sometimes the only local wood, in the South and Mountain West. Burns hot and fast. Missouri Extension rates southern yellow pine "fair" and flags "high sap risk for creosote accumulation" if burned poorly.

5. Non-resinous or low-density softwoods

Definition: Spruce, true firs, white pine, hemlock, eastern redcedar. How to identify: Light, straight-grained, often aromatic; redcedar has red heartwood and a sharp scent. Typical heat value: About 14 to 20 million BTU per cord. When it applies: Kindling and fast-starting fires; the dry, well-seasoned pieces burn cleanly but quickly. Redcedar is rated "fair; good for kindling" and throws sparks.

6. Processing categories: green, seasoned, kiln-dried and heat-treated

Note that "kiln-dried" and "certified heat-treated" are not automatically the same thing. Kiln drying is about moisture; heat-treatment certification is about pest control and comes with a regulatory label. Only the label proves the wood meets a pest-treatment standard.

The table below combines heat values and densities from the Engineering ToolBox wood-combustion table (values are for dry wood at roughly 20% moisture) with burning traits from University of Missouri Extension guide G5450 where that guide rates the species. "—" means the source did not list a value. Seasoning times are general guidance ranges by wood class, built from EPA's six-month minimum and Missouri Extension's note that most dense hardwoods need at least a year; your climate, split size and stacking can shorten or lengthen them.

Table 1: 32 common firewood species

What the numbers mean for your wallet

Heat per cord is the fairest way to compare prices. If seasoned oak costs $400 per cord at about 24–25.7 million BTU, you pay roughly $15.60–$16.70 per million BTU. If cottonwood costs $200 per cord at 13.5 million BTU, you pay about $14.80 per million BTU, which looks similar, but you will load the stove about twice as often and fill twice the storage space. Dense wood also produces longer coal beds, which matters for overnight burns in a stove.

For scale, Missouri Extension calculates that one cord of hardwood air-dried to 20% moisture, burned in an appliance at 50% efficiency, delivers about the same heat as 108 gallons of No. 2 heating oil, 165 gallons of propane, 150 therms of natural gas or 3,341 kWh of electricity.

Step-by-step seasoning process

1. Cut to length for your appliance, usually 2 to 3 inches shorter than the firebox depth or width, so logs load without touching the glass or door.
2. Split promptly. Wood dries mainly through its ends and split faces; bark slows drying. Missouri Extension notes that drying "usually requires several months" after cutting and splitting.
3. Split to size. Pieces about 3 to 6 inches across dry faster and burn more completely in stoves than large rounds.
4. Stack off the ground on pallets, rails or blocks. DOE suggests storing wood elevated about one foot off the ground.
5. Stack loosely in single rows with the bark side up on the top layer, oriented so prevailing wind can pass through the pile.
6. Cover only the top. EPA Burn Wise: "Store wood outdoors, off the ground, with only the top covered—covering the sides traps in moisture."
7. Give it time. At least six months (EPA), at least a year for most dense hardwoods (Missouri Extension), and often longer for oak.
8. Test before burning with a moisture meter (next section).

Table 2: Seasoning time guidance by wood class

Guide ranges assume dry climates dry faster and humid, shaded or poorly ventilated stacks dry slower. Always confirm with a meter.

A pin-type wood moisture meter costs an estimated $25–$60 and is the single cheapest tool for reducing chimney maintenance. EPA Burn Wise recommends testing wood with a moisture meter before you burn it.

How to take an accurate reading

1. Bring a few pieces indoors to room temperature for a day if it is below freezing outside; many meter manuals call for temperature correction on cold or frozen wood.
2. Split a piece in half. The outside of a log dries first, so a reading on the surface can show 15% while the core is 30%.
3. Press the pins into the fresh split face, across the grain if the manual says so, near the middle of the piece.
4. Read three pieces from different parts of the stack.
5. Set the species setting if your meter has one.

Table 3: Moisture readings and what to do

Other quick checks: seasoned wood "sounds hollow when hit against another piece of wood" (EPA Burn Wise), shows cracks (checks) on the ends and is noticeably lighter. Wet wood hisses, sizzles or bubbles at the ends when burning.

Good storage keeps dry wood dry and keeps pests and fire hazards away from the house.

Storage checklist

• Stack outdoors, off the ground (pallets, rails or blocks; DOE suggests about a foot of elevation).
• Cover the top only; leave the sides open to air (EPA Burn Wise).
• Face the long side of the stack to the prevailing wind and give it sun where possible.
• Leave a gap between rows and between the stack and any wall so air can circulate.
• Keep the main stack away from the house rather than against siding, where it can hold moisture against the wall and give insects and rodents a path indoors.
• Bring in only what you will burn in the next few days, and keep indoor wood at least 3 feet from the fireplace or stove (the 3-foot clearance from heat sources is USFA and NFPA guidance).
• Rotate stock: burn the oldest, driest wood first and stack new deliveries in a separate row.
• Check the top layer after storms; replace tarps that pool water.

Table 4: Storage methods compared

Costs are estimated 2026 retail ranges.

The legal cord

A cord is the standard US unit for firewood. It is "the amount of wood that, when 'racked and well stowed,' occupies a volume of 128 cubic feet," usually a stack 4 feet high, 4 feet deep and 8 feet long. NIST Handbook 130, the model weights-and-measures law many states adopt, defines the cord and sets uniform rules for selling fireplace and stove wood (see the NIST Handbook 130 page and Wikipedia summary in Sources). Several states allow firewood to be sold only by the cord or fractions of a cord, to avoid confusion over informal units.

A cord is not 128 cubic feet of solid wood. Missouri Extension notes that the actual solid wood in a cord averages about 80 cubic feet in the Midwest; the rest is bark and air.

The face cord and rick

A "face cord" or "rick" (the Midwestern term) is a stack 4 feet high and 8 feet long but only one log length deep. With 16-inch pieces, that is one-third of a cord. Missouri Extension describes face cords 18 to 24 inches deep and warns they are often misrepresented as a full cord. Because depth varies with log length, the only way to compare is to calculate volume.

Table 5: Firewood units compared

How to calculate what you actually got

Multiply height x length x depth in feet, then divide by 128. A stack 4 feet high by 10 feet long with 16-inch (1.33-foot) pieces is 4 x 10 x 1.33 = 53.2 cubic feet, or about 0.42 cord. If you paid a "full cord" price for that, you paid more than double the fair rate.

Step-by-step: buying firewood without getting shorted

1. Ask for the price in cords or fractions of a cord, not "a load" or "a rick."
2. Ask the species and whether it is seasoned, kiln-dried or green, and when it was cut and split.
3. Ask the piece length so you can calculate face-cord volume and confirm it fits your firebox.
4. Get a written receipt that states the seller's name and address, the quantity in cords, the price and the species or mix. A written record is what a weights-and-measures inspector will ask for if you later file a complaint.
5. Stack the delivery before paying in full if you can, or at least measure the load. A thrown pile of one cord should stack to about 128 cubic feet.
6. Check moisture on delivery by splitting three pieces and metering the fresh faces.
7. Report short measure to your state or county weights and measures office (often in the state department of agriculture), which handles firewood quantity complaints.

Table 6: What drives firewood prices (estimated)

We did not find a reliable, current national price survey for firewood, so treat any single number as local. Ask two or three sellers and compare on a cost-per-cord basis.

Firewood is one of the easiest ways for invasive insects and tree diseases to travel. The Don't Move Firewood campaign's core message is "buy it where you'll burn it": buy locally, buy certified heat-treated firewood, or gather on site where permitted. USDA APHIS gives the same advice: "Buy only local firewood or certified heat-treated firewood."

Key facts on the emerald ash borer (EAB), the pest that drove many firewood rules:

• EAB infestations have been detected in 38 states and the District of Columbia (USDA APHIS).
• APHIS removed its domestic EAB quarantine regulations; the final rule took effect January 14, 2021. That ended the federal EAB firewood quarantine, but it did not end all firewood rules. States, parks and campgrounds can and do keep their own restrictions on firewood movement for EAB, spotted lanternfly and other pests.

Firewood movement checklist

• Check the Don't Move Firewood interactive map for your state's rules before a trip.
• Check the park or campground's rules; many accept only local or certified heat-treated wood.
• If you move wood, choose bundles with a state or USDA heat-treatment certification label.
• Do not bring leftover campfire wood home; burn it or leave it for the next camper where allowed.
• Contact your state department of agriculture or state forestry agency with questions about local quarantines.

EPA Burn Wise lists materials that release toxic chemicals or damage appliances: household trash, coated, painted or pressure-treated wood, driftwood, plywood, particle board, wet, rotted, diseased or moldy wood, plastic, asbestos, rubber and animal remains.

Table 7: Materials to avoid and why

These are illustrative scenarios, not real customers. Prices are estimates; firewood prices vary widely by region.

• Order next season's wood in spring or early summer so it can dry.
• Confirm price per cord, species, piece length and cut date in writing.
• Measure and meter the delivery.
• Stack off the ground, top covered, sides open.
• Keep the main stack away from the house; bring in only a few days' supply.
• Meter three split pieces before the first fire; burn only below 20%.
• Follow local and park rules on moving firewood.
• Book your annual chimney inspection; see best time to sweep a chimney.