A cord of wood lasts anywhere from six weeks to an entire winter. That range is not vagueness, it is the honest answer: how long a cord lasts depends almost entirely on how many hours you burn it, and that varies by a factor of ten between households.
Here is how to work out your own number rather than adopting someone else’s.
What actually decides it
Run hours, not house size. This is the one people get wrong. A stove burning 16 hours a day gets through wood roughly four times faster than one lit for evening fires, regardless of the square footage it is heating. Insulation and house size affect how much heat you need, but the fuel consumption follows the hours the stove is actually running.
Species. A cord of hickory holds roughly 27.7 million BTU. A cord of cottonwood holds about 13.5 million. Same volume, roughly half the heat, so roughly half the burn time at the same output. If you are switching species, your consumption changes even though nothing about your habits did.
Appliance efficiency. A modern EPA certified stove extracts 70 to 80 percent of the wood’s energy. An open fireplace delivers perhaps 10 to 15 percent to the room, and can be net negative on a cold night once you account for the heated air it pulls up the chimney. The same cord goes very different distances.
Moisture. Wood at 50 percent moisture spends a large share of its energy boiling off water rather than heating the room. Burning green wood does not just waste heat, it makes the cord run out sooner while producing more creosote.
Climate. The heating season in Denver is roughly 200 days. In Houston it is under 100. That alone doubles the annual requirement before any other factor.
Typical consumption
| How you burn | Cords per season | One cord lasts |
|---|---|---|
| Occasional fires, weekends only | 0.5 to 1 | The whole season |
| Regular evening fires | 1 to 2 | Two to four months |
| Supplemental daily heat | 2 to 3 | Six to ten weeks |
| Primary heat, moderate climate | 3 to 4 | Six to eight weeks |
| Primary heat, cold climate | 4 to 6 | Five to seven weeks |
These assume seasoned hardwood in a reasonably efficient stove. Softwood, an open fireplace, or green wood all shorten the figures, and can easily do so by half.
Working out your own figure
If you already burn, the reliable method is to measure rather than estimate: note the date you start a fresh cord and the date it runs out, in a normal week of the season. That single observation beats any table, because it captures your stove, your wood and your habits at once.
If you are starting out, work forwards from run hours. A stove burning at a moderate output gets through roughly one cord every six to eight weeks of continuous winter running. Halve the hours and you double the duration.
For a cost comparison against other fuels, the heating cost comparison converts a cord price into a cost per million BTU, which is the only basis on which wood, pellets, gas and propane can honestly be compared.
How much to order
Order for the season, not for the month, and order in spring.
The reason is not just price, although buying in April rather than January typically saves 30 to 40 percent. It is that firewood improves in storage while almost every other purchase decision does not. Green wood bought in spring is seasoned wood by November, and it cost you green wood money.
Round up rather than down. Wood that is properly stacked keeps for years with minimal loss, so an extra half cord is deferred, not wasted. Running short in February means buying at peak price from whoever still has stock, which is usually the yard with the wettest wood.
A practical rule: take your estimate from the table above, add half a cord, and buy the lot in one delivery. One delivery of three cords almost always costs less in freight than three deliveries of one, since the yard is quoting the truck and the driver either way.
Making a cord last longer
Most of the available savings are in how the wood is prepared and burned, not in rationing it:
- Season it properly. Under 20 percent moisture. This is the single largest factor, and it is free if you buy early enough.
- Burn hot, not smouldering. Damping a stove down to make wood last produces less usable heat and more creosote. A hot clean burn extracts more of the energy you paid for.
- Match the species to the job. Softwood for kindling and shoulder season, dense hardwood for overnight burns. Using oak to take the chill off an October evening wastes its main advantage.
- Stack it off the ground, covered on top only. Wood stored on soil under a full tarp reabsorbs moisture and can end the summer wetter than it started.
Check what you were actually delivered
All of this assumes you received a full cord. Before estimating how long it will last, confirm the volume: stack it tightly and measure, since a loose pile occupies roughly one and a half times the space of the same wood stacked.
The cord of wood calculator converts your stack measurements to cords, and handles face cords and ricks at any cut length. If the quantity is short, no amount of careful burning makes it up.