Ask on any wood-stove forum and you'll get answers from two tons to eight. They're all right for somebody: the amount depends on how much of the house the stove heats, how cold your winters are, and how well the house holds heat. These tables give a starting point for each, built on published heat values rather than anecdotes, so you can buy close to what you'll burn.
Tons of Pellets for a Winter
For a typical existing house with the pellet stove as the only heat source, burning premium pellets (16.4 million BTU per ton) in a stove at EPA's 78% default efficiency. A ton is 50 bags of 40 lb.
| Climate | 1,000 sq ft | 1,500 sq ft | 2,000 sq ft | 2,500 sq ft | 3,000 sq ft |
|---|---|---|---|---|---|
| Hot Atlanta, Dallas | 0.6 t 31 bags | 0.9 t 47 bags | 1.3 t 63 bags | 1.6 t 78 bags | 1.9 t 94 bags |
| Mixed Chicago, DC, Denver | 1.4 t 70 bags | 2.1 t 106 bags | 2.8 t 141 bags | 3.5 t 176 bags | 4.2 t 211 bags |
| Cold Boston, Hartford | 2.2 t 109 bags | 3.3 t 164 bags | 4.4 t 219 bags | 5.5 t 274 bags | 6.6 t 328 bags |
| Very cold Minneapolis, Buffalo | 3.1 t 156 bags | 4.7 t 235 bags | 6.3 t 313 bags | 7.8 t 391 bags | 9.4 t 469 bags |
So a 2,000 sq ft home in a Chicago-type climate needs about 3 tons; the same house near Boston about 4.5, and near Minneapolis about 6. If the stove shares the job with a furnace or heat pump, scale down by the share it covers: a stove that heats the living area of a 2,000 sq ft house, roughly half the load, needs about half the tons.
Buy a little over the table. Pellets keep for years if stored dry, and running short in February means paying peak prices or switching back to propane at the worst time.
Cords of Firewood for a Winter
Seasoned firewood holds about 20 million BTU per full cord (4 × 4 × 8 ft). EPA's default efficiency is 63% for certified non-catalytic stoves and 72% for catalytic ones; the smaller figure in each cell is for a catalytic stove.
| Climate | 1,000 sq ft | 1,500 sq ft | 2,000 sq ft | 2,500 sq ft | 3,000 sq ft |
|---|---|---|---|---|---|
| Hot Atlanta, Dallas | 0.6 0.6 cat. | 1.0 0.8 cat. | 1.3 1.1 cat. | 1.6 1.4 cat. | 1.9 1.7 cat. |
| Mixed Chicago, DC, Denver | 1.4 1.2 cat. | 2.1 1.9 cat. | 2.9 2.5 cat. | 3.6 3.1 cat. | 4.3 3.8 cat. |
| Cold Boston, Hartford | 2.2 1.9 cat. | 3.3 2.9 cat. | 4.4 3.9 cat. | 5.6 4.9 cat. | 6.7 5.8 cat. |
| Very cold Minneapolis, Buffalo | 3.2 2.8 cat. | 4.8 4.2 cat. | 6.3 5.6 cat. | 7.9 6.9 cat. | 9.5 8.3 cat. |
Three things change these numbers more than the stove does:
- Moisture. The 20 million BTU figure is for wood dried to about 20% moisture. Green wood holds much less usable heat and burns poorly, so a cord of it goes much faster.
- Species. Dense hardwoods like oak, hickory and sugar maple carry more heat per cord than pine, poplar or soft maple. Heat value tracks weight, and a cord of dense hardwood weighs far more than a cord of light softwood.
- What "a cord" means. A full cord is 128 cubic feet. A face cord, rick or "truckload" is often a third of that, so check the dimensions before comparing prices.
How Many Bags of Pellets Per Day
Daily use follows the weather. For a typical existing house that needs about 3 BTU of heat per square foot for every degree the day's average falls below 65°F (the mixed-climate figure our heating calculators use), burning 40-lb bags:
| Outdoor average | 1,500 sq ft | 2,000 sq ft | 2,500 sq ft |
|---|---|---|---|
| 45°F | 0.4 bags 14 lb | 0.5 bags 19 lb | 0.6 bags 23 lb |
| 35°F | 0.5 bags 21 lb | 0.7 bags 28 lb | 0.9 bags 35 lb |
| 25°F | 0.7 bags 28 lb | 0.9 bags 38 lb | 1.2 bags 47 lb |
| 15°F | 0.9 bags 35 lb | 1.2 bags 47 lb | 1.5 bags 59 lb |
| 5°F | 1.1 bags 42 lb | 1.4 bags 56 lb | 1.8 bags 70 lb |
At a 25°F day-and-night average, a stove heating 2,000 sq ft burns about a bag a day; in a 5°F cold snap, closer to a bag and a half. A drafty older house can burn noticeably more, a tight newer one less. If your stove goes through two or three bags a day in mild weather, it's either heating far more area than you think or losing heat somewhere worth fixing.
Is It Cheaper Than What You Heat With Now?
At $350 a ton, three tons of pellets is about $985 for a season. That's well below propane (about $1,230 for the same heat at $2.50 a gallon) or heating oil (about $1,160 at $3.80), but more than natural gas or a heat pump (about $765). The pellet and firewood cost calculator runs that comparison with your prices and shows the pellet price at which each fuel breaks even.