Finding the right firewood can be a real headache especially if you are not experienced with the whole process. Different wood species produce different amounts of heat and burn for different amounts of time. You can end up using a lot of firewood if you go for the wrong species. Let’s take a look at the heat outputs for the different tree species.
Hardwoods produce the highest amount of heat, with Osage Orange producing the highest amount of heat of 32.9 million BTUs per cord. Some other species with high heat outputs include Shagbark Hickory, Black Birch, Honey Locust.
What Wood Burns the Hottest?
Hardwoods burn the hottest and are considered to be the most efficient firewood. While some softwoods like Cedar, Fir, and Pine can also be used as good firewood, hardwoods are the first choice for everyone.
Below is a table of some of the best Hardwood firewoods along with their BTUs per Cord. These values are at a 20% moisture level.
|Northern Red Oak||24|
|Kentucky Coffee Tree||20.8|
But some softwoods are also great choices for firewood. A lot of times they can be bought at much cheaper rates.
|Rocky Mountain Juniper||21.6|
|Eastern White Pine||14.3|
|Eastern White Cedar||12.2|
What Makes a Good Firewood?
There are two major factors that determine the efficiency of firewood. The first is the moisture content of the firewood you are using. The higher the moisture content, the lower its efficiency. A large part of the energy will be utilized in evaporating the moisture within the wood and the heat output will be lower.
A moisture content of more than 20% is not recommended for firewood. Anything above this will also produce a lot of smoke. This is why you should ensure that the firewood you are using has been properly seasoned.
The next factor is the density of the wood species you are dealing with. Higher density entails that a lot more fuel has been packed into the same volume of wood.
How to Determine the Heat Produced by Firewood?
Most commonly, the British Thermal Unit or BTU is used to measure the thermal output of timber. 1 BTU is defined as the energy it takes to heat 1lb of water by 1F.
Check out our BTU table compiling more than 160 species of firewood here.
Another important term which you need to know is a ‘cord’. The heat output of firewood is usually calculated in terms of BTUs per cord. 1 cord of firewood is the amount of wood in 4X4X8 ft volume. This equates to 128 cubic feet.
But the actual firewood volume is reached by subtracting the air space and the volume of the bark within the cord. This comes to about 75-100 cubic feet.
The higher the BTUs per cord, the higher the heat output.
Hardwood firewood species like Osage Orange, Shagbark hickory, Birch, Red Oak produce the most amount of heat. Softwoods, on the other hand, have lower efficiency and even produce a lot of smoke, although some species can be used as good firewood. Osage Orange has the highest heat output with 32.9 BTUs/cord.
I am the guy behind Theyardable.com. I grew up on a homestead and I am here to share the knowledge I have and things I learn while living in the countryside.