Are you on the hunt for the ultimate firewood? While there are several factors to consider when choosing wood, British Thermal Unit (BTU) rating is one of the most important.
This guide provides a handy comparison of common wood species and a BTU firewood chart that you can download. It’ll help you make the best choice for your home heating needs.
BTU chart for firewood
From 57 common hardwood and softwood varieties, we calculated the average BTU was 23.51. The lowest BTU was poplar at 13.7, and the highest was mountain mahogany at 39.8.
Check out the wood BTU table below to learn more.
|Type of Wood||BTU (millions) Per Cord|
What does BTU actually mean?
BTU, or British Thermal Units, is a helpful way to compare the heat output of different types of wood. One BTU is the heat required to increase the temperature of one pound of water by one degree Fahrenheit.
When evaluating firewood, the industry measures heat output in million BTUs per cord of wood. One cord is a stack with dimensions 4’x4’x8′ or 128 cubic feet.
The denser the wood from a tree variety, the higher the BTUs per volume. That means hardwoods typically provide better heat efficiency than softwoods, although some exceptions exist. Check out our comparison of hardwoods and softwoods here.
- On a per-pound basis, all wood has a similar BTU.
- Hardwoods are mostly denser than softwoods, so they provide higher BTU per Cord.
- One pound of resinous wood offers roughly 8600-9700 BTU.
- One pound of non-resinous wood provides 8000-8500 BTU.
What factors affect the BTU for wood?
Moisture is the most significant factor influencing BTU in firewood. The heating value of wood reduces by 1% for every 1% increase in moisture content. The energy that should be providing heat is used to evaporate water instead. A bone-dry piece of wood (0% moisture) that offers 7,000 BTUs per pound will only provide 3,500 BTUs at 50% moisture.
The other major factor affecting BTU is tree species. Most hardwoods have a dense structure, producing greater heat output per cord.
How can I maximize my firewood’s BTU output?
To get the most heat from your wood, properly season it before burning. Moisture content should be less than 20% for best results, according to the EPA.
The drying process is simple but takes time. Allowing the stack of wood to cure will slowly remove the moisture, increasing the wood’s BTU output. You can get some practical advice on stacking the wood by reading our firewood storage resource.
Seasoning times vary by the species of wood. Softwoods generally take 6-12 months to season, while hardwoods range from 12-36 months.
How do I know when the wood is ready to burn?
A common way to tell if firewood is okay to burn is to bang two pieces together. If they sound hollow, they’re most likely ready to burn.
The more exact approach is to use a moisture meter, an affordable, easy-to-use tool. A moisture meter has two sharp electrodes which get pushed into the wood. The resistance between each electrode will show the levels of moisture.
How important is BTU when choosing firewood?
BTU is a valuable metric to consider when choosing firewood. Consider a supplier selling pine and oak for the same price in your local town. Based on BTU, you’ll get a lot more “bang for your buck” from the oak, which is a hardwood.
While BTU is good to know, it is only one factor. You should also check how easy the wood is to split, whether it burns clean in the fire, its tendency to spark, and its fragrance.
Can firewood burn too hot?
While a cozy, warm home is desirable, some wood burns so hot that it can damage woodstoves. Wood like manzanita, mountain mahogany, and eucalyptus can reach incredibly high temperatures. One way to overcome this problem is to mix a hot-burning wood with another less intense variety.
What are the limitations of a BTU chart?
The biggest problem with calculating firewood BTU is that a cord can vary significantly in mass. One cord is always 128 cubic feet, but the amount of wood packed into that space depends on log shape, size, and how well it is stacked.
Low BTU isn’t all bad. In fact, a lower-rated wood like poplar may work fine in your home. It just means topping up the fire more often. Those living in milder climates may find low-BTU firewood acceptable, especially if it’s cheaper.
How does wood BTU heat production compare to other sources of heat?
The average BTU output from our firewood list was 23.51 million per cord. In comparison, one ton of anthracite coal gives off 26 million BTUs of heat. Here are some other fuel sources and the heat efficiency they offer.
|Electricity||1 kilowatt hour = 3,412 BTU|
|Natural gas||1 cubic foot = 1,039 BTU|
|Gasoline||1 gallon = 120,238 BTU|
|Propane||1 gallon = 91,452 BTU|
Firewood BTU charts are a useful way to understand how efficiently wood provides heat. Higher values mean the wood is denser, so it’ll burn slower. Frequent trips to the woodpile won’t be needed.
Don’t get too obsessive about BTU. Visit any firewood forum online any you’ll often see experienced firewood users post, “if it burns, I’ll burn it”. Season the wood properly and you’ll stay warm this winter.
Have you got a specific wood variety in mind? Check out our eBook, the Ultimate Guide To Firewood, to get the complete picture on practically every tree species you’re likely to burn.
1. Burning Wood and Coal by Susan Mackay, L. Dale Baker, John W. Bartok, Jr., and James P. Lassoie. 1985. Northeast Regional Agricultural Engineering Service, Riley Robb Hall, Cornell University, Ithaca, NY 14853. (607)256-7654. 90 pp.
2. The Ultimate Guide To Firewood by Alex Johansen. 2022. Amazon Publishing.
3. The Wood Burner’s Encyclopedia by Jay Shelton and Andrew B. Shapiro. 1976. Vermont Crossroads Press, Box 333, Waitsfield, VT 05673. 155 pp.