Wood stove BTU output = heated square feet × BTU per sq ft for your climate zone, so a 1,500 sq ft home in zone 4 with average insulation needs about 71,000 BTU per hour, which points to a stove with a firebox around 2 cu ft. Enter your area and zone above to get the output, the size class and real stove models that cover it.
How the wood stove size calculator works
The calculator reuses the heating engine behind the BTU calculator and the furnace size calculator. InspectAPedia's zone table gives a heat need per square foot for each IECC climate zone: zone 1 30 to 35 BTU/h, zone 2 35 to 40, zone 3 40 to 45, zone 4 45 to 50, zone 5 50 to 60; we use Bryant's cold band of 50 to 60 for zones 6 and 7. Good insulation sits at the low end of the band, a leaky older house at the high end, and ceilings taller than 8 ft scale the load by height ÷ 8.
Stove output (BTU/h) = heated area (sq ft) × BTU/h per sq ft × (ceiling ÷ 8 ft) × share of the load
Choose "Extra heat" when the stove backs up a furnace or heat pump and only has to carry half the load (our assumption; the calculator applies 50%).
Worked examples
- 1,500 sq ft, zone 4, average insulation: 1,500 × 47.5 = 71,250 BTU/h. The smallest listed stove that covers it is the Pacific Energy Super 27 LE, 72,000 BTU/h with a 2.0 cu ft firebox.
- Same home as backup heat: 35,625 BTU/h, covered by the Hearthstone Castleton 8031 at 45,000 BTU/h.
- Same home, older and leaky (high end, 50 BTU/h per sq ft): 75,000 BTU/h, the Hearthstone Manchester 8362 at 78,000 BTU/h and a 2.9 cu ft firebox.
- 600 sq ft cabin in zone 4: 28,500 BTU/h, still the smallest listed model, the Castleton at 45,000 BTU/h.
- 2,400 sq ft in zone 5: 132,000 BTU/h, more than any listed stove gives, so plan a second heat source.
Wood stove size chart: firebox, BTU and heating area
Hearth.com's comparison chart lists these models with the manufacturers' own numbers.
| Model | Firebox | Maximum output | Manufacturer's heating area |
|---|---|---|---|
| Hearthstone Castleton 8031 | 1.9 cu ft | 45,000 BTU/h | 800 to 1,500 sq ft |
| Hearthstone Shelburne 8371 | 2.0 cu ft | 50,000 BTU/h | 1,200 to 1,800 sq ft |
| Hearthstone Heritage 8024 | 2.2 cu ft | 60,000 BTU/h | 1,200 to 2,000 sq ft |
| Pacific Energy Super 27 LE | 2.0 cu ft | 72,000 BTU/h | 1,200 to 2,000 sq ft |
| Hearthstone Manchester 8362 | 2.9 cu ft | 78,000 BTU/h | 1,800 to 2,400 sq ft |
| Hearthstone Mansfield 8012 | 3.2 cu ft | 80,000 BTU/h | 1,800 to 2,500 sq ft |
| Pacific Energy Neo 2.5 | 2.5 cu ft | 85,000 BTU/h | 1,500 to 2,300 sq ft |
| Pacific Energy Summit LE | 3.0 cu ft | 99,000 BTU/h | 2,000 to 3,000 sq ft |
These are examples of the size range, not recommendations. Maximum output is a peak the stove reaches with a full load of dry wood, and heating area is the manufacturer's claim for a well laid out house in a moderate climate. Regency's classes, for average single-storey homes in a moderate climate: small under 500 sq ft, medium 500 to 1,000, large 1,000 to 2,200, extra-large above 2,200.
What size wood burner for my house?
EPA's Burn Wise guidance says small stoves suit a family room or seasonal cottage, medium stoves small to medium energy-efficient homes, and large stoves larger open-plan or older, leakier houses in colder zones. Take the calculator's output as a starting point and bring your floor plan to a dealer, as EPA suggests. Open layouts let heat move; a stove in one end of a house with closed doors and a second floor will not warm the far bedrooms.
Why bigger is not better
An oversized stove is turned down to keep the room comfortable, and a damped fire smolders. Regency warns that oversizing forces "smaller fires", which lead to creosote build-up in the chimney. If the result falls between two models, choose the smaller and run it hotter.
How much wood the stove will burn
The output tells you the size; the wood tells you the cost. Estimate a season's fuel in the firewood calculator, which turns the same floor area and climate into cords per winter, and compare with the propane usage calculator and the heat pump size calculator. For one heated room instead of a house, try the space heater calculator.
Safety
The US Fire Administration says to keep anything that can burn at least 3 feet from wood stoves and other heat sources, and to have heating equipment and chimneys professionally inspected and cleaned every year. EPA-certified stoves also use about a third less wood than older ones, and a certified installer knows the local code for the flue, hearth and wall clearances. The stove's own label lists the clearances it was tested at. All the heating tools are in the heating and plumbing calculators hub.