Cord-Wood BTU by Species
A quick reference for how much heat a cord holds by species — context for a wood-burning hearth, not a firewood market.
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Denser hardwoods pack more heat per cord and burn cleaner when seasoned — Oak is about 24 million BTU per cord. A quick reference only; firewood seasoning and cord economics are out of scope here — this is just context for a wood-burning hearth.
This one is deliberately minor — firewood seasoning and cord economics are their own subject and are out of scope here. What is useful in a chimney context is the rough idea that species matters: a cord of dense hardwood carries far more heat, and burns cleaner when seasoned, than the same volume of softwood. That directly affects how hard your flue works and how fast it builds creosote.
Heat content is quoted in million BTU (MBTU) per cord — a stacked 4 × 4 × 8 ft pile, 128 cubic feet. Dense hardwoods sit at the top: hickory around 27 MBTU per cord and oak around 24. Medium hardwoods like maple (~22) and birch (~20) are a step down. Softwoods such as pine land near 15 and burn fast and hot with more sparks and pitch. The practical takeaway for a hearth: seasoned hardwood gives long, steady, hot burns that keep the flue warm and creosote low, while wet wood or a lot of low-grade softwood cools the flue and glazes it — the exact pattern that pushes you toward the higher creosote stages.
Two things matter more than the exact number in the table. The first is moisture: freshly cut "green" wood can be half water by weight, and burning off that water steals heat and cools the flue, so unseasoned oak can behave worse in a chimney than well-dried pine. Split it, stack it off the ground with the top covered, and give hardwood a year or more to season toward roughly 20% moisture; an inexpensive moisture meter settles the argument. The second is resin: softwoods like pine carry more pitch, which pops, throws more sparks and can add to deposits when burned cool — fine as kindling and for a hot start, less ideal as the all-night fuel. None of that requires you to optimize a wood budget here; it just explains why species and dryness show up on a chimney site at all — they set how hard your flue works and how often it needs a sweep.
Worked example
You have a choice between a cord of well-seasoned oak (~24 MBTU) and a cheaper cord of green pine (~15 MBTU). The oak is not just ~60% more heat per cord — because it burns hotter and drier, it keeps the flue warm and lays down less creosote, so it is easier on the chimney too. The pine, especially unseasoned, cools the flue and glazes it faster. For a chimney you want to keep clean, the denser, drier wood is the better neighbor to your flue.
A minor reference — scope note
Scope note: this is a hearth-side reference, nothing more. It does not price firewood, size a wood order, or model seasoning time — those belong to a firewood tool, not a chimney site.
What actually matters for the flue: moisture more than species. Any wood burned wet cools the flue and makes creosote; target seasoned wood at roughly 20% moisture or below. General wood-heat background is available from the EPA Burn Wise program. Treat the numbers here as a rough ranking, not a spec: they vary with density, growing region and how well the wood was dried.
Reference table
| Species | Heat content | Class |
|---|---|---|
| Hickory | 27 MBTU/cord | Dense hardwood |
| Oak | 24 MBTU/cord | Dense hardwood |
| Maple | 22 MBTU/cord | Medium hardwood |
| Birch | 20 MBTU/cord | Medium hardwood |
| Pine / softwood | 15 MBTU/cord | Softwood |
Million BTU per cord of seasoned, split wood — a rough reference, not a fuel-market figure.
Frequently asked questions
What is a cord of wood?
A cord is a stacked pile measuring 4 feet high by 4 feet wide by 8 feet long — 128 cubic feet of wood and air. Heat content here is given in million BTU per cord so species can be compared on the same basis.
Is hardwood really better than softwood?
For a hearth, generally yes: dense hardwoods like oak and hickory pack more heat per cord and give long, steady burns that keep the flue warm and creosote low. Softwoods burn fast and hot with more sparks and pitch, which is harder on a chimney.
Does seasoning matter more than species?
Often, yes. Any wood burned wet cools the flue and glazes it with creosote, so a well-seasoned softwood can beat green hardwood for chimney health. Aim for seasoned wood at about 20% moisture or below whatever the species.
Why not just burn pine?
You can burn seasoned pine, but it has less heat per cord, burns quickly, and its pitch and lower flue temperatures from fast burns can encourage creosote. Many people use softwood for kindling and a hot start, then hardwood for the long burn.
How can I tell if firewood is dry enough to burn?
Dry, seasoned wood is lighter, gray and checked (cracked) at the ends, and two pieces knocked together give a sharp crack rather than a dull thud. The reliable test is an inexpensive moisture meter on a freshly split face, aiming for roughly 20% or below. Wet wood hisses and bubbles at the ends when it burns — a sign it is cooling your flue and feeding creosote rather than heating the room.