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Reviewed · Climate: NOAA hourly records, 2015-2024 · How we calculate

Wood Stove Size Calculator: What Size Stove Do I Need?

Enter your ZIP code and the part of the house the stove will heat. You get the heat it loses on the coldest nights and on a mild day, the range a stove's tested heat output should cover, instead of a square-foot guess.

Inputs

Climate for Kansas City, MO, zone 4A

°F

Colder than this only 1% of the year

sq ft

Heated and cooled area

ft

Average is double-pane windows and a typical 1990s-2010s house.

people

Your wood stove

Updates as you type
29,600BTU/h

on a 9°F night; about 14,600 BTU/h on a 40°F day

Look for a stove whose EPA-tested heat output range reaches about 29,600 BTU/h at the top and goes down to about 14,600 at the bottom.

Show the math
Walls: 5,000 BTU/hCeiling: 3,600Windows: 8,200Floor edge: 5,700Outside air leaking in: 7,100Total: 29,600 BTU/h at ΔT 61°F (no ducts: a stove heats the room it's in)

Climate data: NOAA / DOE, zone 4A, design temps 92°F / 9°F, Kansas City, MO.

Estimate only: check the product’s installation instructions and your local code.

The short answer

An 1,800 sq ft one-story house with average insulation loses about 36,900 BTU/h on a design night in Minneapolis (-6°F) and 14,600 BTU/h on a 40°F day, so a stove for the whole space should have a tested heat output range from about 14,600 to 36,900 BTU/h. In Houston (37°F) the same house needs only about 16,000 BTU/h at most. Heating one 600 sq ft open area in Minneapolis takes about 15,900 BTU/h.

The same space in every state

An 1,800 sq ft, one-story space with average insulation, at the winter design temperature of each state's largest city.

Wood stove heat need for the same space in each state. Select a column heading to sort.
Alabama Huntsville3A2322,80012,600
Alaska Anchorage7-436,00014,600
Arizona Phoenix2B4313,1007,800
Arkansas Little Rock3A2521,90012,100
California Los Angeles3B4711,2006,800
Colorado Denver5B730,60014,600
Connecticut Bridgeport5A1626,20014,300
Delaware Wilmington4A1825,30013,800
District of Columbia Washington4A2322,80012,600
Florida Jacksonville2A4213,6008,000
Georgia Atlanta3A2720,90011,700
Hawaii Honolulu1A661,9002,200
Idaho Boise5B1626,20014,300
Illinois Chicago5A631,10014,600
Indiana Indianapolis4A929,60014,600
Iowa Des Moines5A034,00014,600
Kansas Wichita4A1327,70014,600
Kentucky Louisville4A1626,20014,300
Louisiana New Orleans2A4014,6008,500
Maine Portland6A730,60014,600
Maryland Baltimore4A1924,80013,600
Massachusetts Boston5A1427,20014,600
Michigan Detroit5A929,60014,600
Minnesota Minneapolis6A-636,90014,600
Mississippi Jackson3A2919,90011,200
Missouri Kansas City4A929,60014,600
Montana Billings6B-436,00014,600
Nebraska Omaha5A432,10014,600
Nevada Las Vegas3B3716,0009,200
New Hampshire Manchester5A929,60014,600
New Jersey Newark4A1725,80014,100
New Mexico Albuquerque4B2322,80012,600
New York New York4A1825,30013,800
North Carolina Charlotte3A2720,90011,700
North Dakota Fargo6A-1340,30014,600
Ohio Columbus4A1128,70014,600
Oklahoma Oklahoma City3A1924,80013,600
Oregon Portland4C3019,40010,900
Pennsylvania Philadelphia4A1825,30013,800
Rhode Island Providence5A1128,70014,600
South Carolina Charleston3A3218,50010,400
South Dakota Sioux Falls6A-436,00014,600
Tennessee Nashville3A2123,80013,100
Texas Houston2A3716,0009,200
Utah Salt Lake City5B2024,30013,400
Vermont Burlington6A034,00014,600
Virginia Virginia Beach3A2720,90011,700
Washington Seattle4C3019,40010,900
West Virginia Charleston4A1626,20014,300
Wisconsin Milwaukee5A432,10014,600
Wyoming Cheyenne5B332,60014,600

How it works

The formula

We add up the heat the space loses, the same block-load method as our furnace calculator, but without duct losses, because a stove heats the room it stands in.

ΔT = 70°F − winter design temp (and 70 − 40 for a mild day; where the design temp is above 40°F, the mild day is halfway between it and 65°F)
walls, ceiling, windows = U × area × ΔT
floor edge = F × perimeter × ΔT
air leaks = 1.08 × CFM × ΔT

Assumptions

  • Enter only the space the stove will heat: an open-plan main floor, a basement, a cabin. Closed-off rooms and upstairs bedrooms get little heat from a stove.
  • Average insulation is R-13 walls (U 0.075), an R-30 attic (U 0.033), double-pane windows (U 0.5) and 0.45 air changes an hour.
  • The design temperature is colder than only 1% of the year's hours, from ten years of NOAA hourly readings at the airport nearest your county.
  • EPA's certified wood heater list gives each stove's tested heat output range in BTU/h; for cordwood stoves it typically runs about 9,000 to 35,000. Advertised maximums (often 60,000 to 90,000 BTU/h) are peak burn rates, not steady heat.

Worked example: 1,800 sq ft in Minneapolis

One story, 8 ft ceilings, average insulation. Winter design -6°F, so ΔT = 76°F.

  1. Walls 6,200 + ceiling 4,500 + windows 10,300 + floor edge 7,100 + air 8,900 = 36,900 BTU/h
  2. On a 40°F day, ΔT = 30°F, so 14,600 BTU/h
  3. Look for a tested heat output range of about 14,600 to 36,900 BTU/h; at the top end, a furnace or second stove covers the coldest nights

Too big or too small

  • Too big: smoldering and creosote. Choking the air to keep from overheating makes smoky, polluting fires and coats the chimney with creosote.
  • Too small: it can't keep up on the coldest nights; plan on a backup heat source anyway.
  • Mind the low end. Most of the winter is mild; a stove that burns clean at low output will be used more and safer.
  • Get it installed right. Clearances, chimney height and a hearth pad matter more than the size; follow the stove's manual and local code, and add CO and smoke alarms.

Questions people ask

What size wood stove do I need?

One whose tested heat output reaches the heat your space loses on a cold night, and that can still burn low on mild days. An 1,800 sq ft house with average insulation in Minneapolis (winter design -6°F) loses about 36,900 BTU/h on the coldest nights and 14,600 on a 40°F day. A 600 sq ft open area there loses about 15,900 BTU/h.

How many square feet will a wood stove heat?

Ignore the square-foot claim on the box: the same stove heats far more in a tight house in a mild climate than in a drafty one up north, and stoves heat the room they stand in far better than closed-off rooms. Size by heat loss: our figure for your ZIP code and house, against the stove's tested heat output range.

What happens if a wood stove is too big?

You have to choke the air down to keep the room from overheating, so the fire smolders. EPA warns that a stove too big for the room or house makes the wood smolder and pollute, and smoldering also builds up creosote in the chimney, a fire risk. A stove that burns hot and clean in short fires, or a slightly smaller one, is better than a big one turned down.

What do the BTU numbers on a wood stove mean?

Two different things. Many makers advertise a maximum burn rate, often 60,000 to 90,000 BTU/h, which a stove reaches only flat out. EPA's certified wood heater list gives each model's tested heat output range instead, typically about 9,000 to 35,000 BTU/h for a cordwood stove. Compare your heat loss with that tested range.

Can a wood stove heat a whole house?

An open-plan, well-insulated house, yes, if the stove stands in the middle of it. Closed doors and long hallways keep heat in the stove room. A drafty 1,800 sq ft house in Minneapolis loses about 57,900 BTU/h on a design night, more than most single stoves deliver steadily, so keep a furnace or heat pump for backup.