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Resources » Facts About Heating with Wood

Facts About Heating with Wood

Wood is the only fuel that heats twice ...
first when you cut and stack it, and again when you burn it!

A cord is a stack of wood 4 feet high, 4 feet wide and 8 feet long. Allowing for air pockets, a cord is approximately 85 cubic feet of wood. On average, a pound of wood produces 8,600 BTUs of heat, regardless of species. So dense heavy woods deliver more heat per cord. Consider this fact when comparing prices for different kinds of wood. It takes about 1,000 BTUs to evaporate each pound of moisture in a log. That is why dry wood produces less creosote and 10-30% more useable heat for your home.

A good time to cut or buy green wood is in late winter or early spring. To dry it as quickly as possible, cut it to length and stack it so that air can circulate through the pile. Also, shelter the stack from the weather and hold it for 18 months before using.

If you cut your trees in the spring or summer, let them lie "unlimbed" until the leaves wither. The withering process draws moisture from the wood. Then, cut the wood to the longest length that will fit in the firebox. The longer the stick, the longer the fire will hold. The amount of heat extracted from a cord of wood varies with the species. The U.S. Forest Products Laboratory compiled the following figures, showing weights and energy content for various species of wood. These figures assume seasoned wood with 20% moisture content.

Wood Species

Cord Weight (lbs)

Energy Content (million BTUs/cord)

Alder

2,708

17.6

Apple

4,140

26.5

Ash, Black

2,992

19.1

Ash, White

3,689

23.6

Aspen

2,295

14.7

Basswood

2,108

13.5

Beech, Blue

3,890

26.8

Beech, High

3,757

24.0

Birch, Black

3,890

26.8

Birch, Gray

3,179

20.3

Birch, Paper

3,179

20.3

Birch, White

3,179

20.3

Birch, Yellow

3,689

23.6

Box Elder

2,797

17.9

Butternut

2,100

14.5

Cedar, White

1,913

12.2

Cherry

3,120

20.0

Cherry, Black

2.880

19.9

Cottonwood

2,108

13.5

Elm, American

3,052

19.5

Elm, Oyen

3,052

19.5

Elm, White

3,052

19.5

Fir, Balsam

2,236

14.3

Fir, Douglas

3,196

20.6

Hackberry

3,246

20.8

Hemlock

2,482

15.9

Hickory

4,327

27.7

Hornbeam, Eastern

4,267

27.3

Locust, Black

3,890

26.8

Maple, Red

2,924

18.7

Maple, Sugar

3,757

24.0

Oak, Red

3,757

24.0

Oak, White

4.012

25.7

Pine, Jack

2,669

17.1

Pine, Norway

2,669

17.1

Pine, Pitch

2,669

17.1

Pine, Ponderosa

2,380

15.2

Pine, Western

2,236

14.3

Spruce

2,100

14.5

Spruce, Black

2,482

15.9

Tamarack

3,247

20.8

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