Seasoned vs. Kiln Dried Firewood: Does It Burn the Same?
When the leaves and the mercury start to fall, it's time to stock up on firewood. Which should you choose: naturally seasoned or kiln-dried?
As you probably know, wood from a newly-felled tree is considered green and essentially worthless as firewood, because the water content hovers around 60 percent. Typically, green wood can be dried two ways: naturally seasoned or kiln-dried. Is one better than the other? Well, yes.
What Is Seasoned Firewood?
Seasoned firewood results from the natural drying process, which can take six to 18 months. Some people recommend waiting three years for the best results!
A lot of factors play into how quickly the wood dries:
- Whether the cut tree was alive or dead when felled;
- The hardness of the wood (pine and other softwoods typically dry faster than hardwoods like oak);
- The season when the wood is cut (warmer months are best);
- How it’s stacked (lots of airflow among the pieces is best).
At the end of the seasoning process, the wood should begin to crack at the edges and its color should be dull and gray. The wood will also weigh less, with the moisture level dropping to around 20 to 30 percent. If you give the wood too much time to season, you run the risk of it decomposing.
What Is Dried Firewood?
Kiln-drying firewood supercharges the natural drying process. Placed in a climate-controlled kiln, the wood bakes between 120 and 220 F with low humidity, typically for three to six days. That lowers the wood’s moisture content below 20 percent, perfect for burning. Kiln-dried firewood will weigh less than naturally seasoned and will sound hollow when tapped.
Seasoned vs. Dried Firewood
So what’s the difference when the fire’s burning? Actually, quite a lot.
- Let’s start with starting the fire. With less residual water trapped inside, dried firewood lights easier and quicker, often with a little kindling and some shredded newspaper.
- Less moisture in the wood also means less smoke, so dried firewood burns cleaner and releases fewer fine particles into the atmosphere. This is important because, according to the Environmental Protection Agency, breathing in too much smoke can irritate and inflame your lungs and negatively impact your immune system. It can also trigger asthma attacks and other health issues.
- Dried wood burns more efficiently, meaning you use less.
- The hotter kiln-drying process destroys residual pesticides and mold, along with invasive pests like the emerald ash borer and Asian longhorn beetle. For that reason, many state and national parks that ban firewood from outside the immediate area will make exceptions for pre-packaged kiln-dried wood.
Naturally seasoned wood is cheaper, typically by about 10 to 30 percent. But when it comes to burning, it’s no contest. In virtually every use, whether for a campfire or cozy blaze in your living room fireplace, kiln-dried firewood is better than traditional seasoned wood.
Note: Even kiln-dried wood isn’t recommended for heating your home. Experts suggest wood pellets, which are even denser and have a moisture content in the single digits.