Wood is a great source of heat. It’s plentiful, it’s renewable, and if you live in the right area, it can be very inexpensive (or downright free). You can’t just cut down a tree and burn the wood right away, though. Rather, it has to go through an extensive seasoning process before you take a match to it.
At HY-C, we manufacture EPA-approved wood burning furnaces under our Shelter and Fire Chief brand names. And getting a wood furnace through the EPA approval process requires a lot of knowledge about firewood. From the best types of wood to burn to understanding BTU measurements, decades of experience have taught us a lot about the right way to burn wood.
In this guide, we’re going to cover one of the most pivotal aspects of getting the most out of your firewood: the seasoning process.
We’ll cover how firewood should be cut, how it should be stacked, how it should be covered, and how long you should let it season. By the time you’re finished here, you’ll know exactly how to prepare your seasonal supply of firewood.
Why Should You Season Firewood?
Seasoning firewood is all about the wood’s moisture content. Specifically, it’s about the best ways to lower the moisture content of freshly cut firewood.
A publication by the University of Missouri found that in Missouri, a pound of freshly cut wood consists of 0.57 pounds of dry firewood and 0.43 pounds of water. That’s nearly 7 ounces of water per pound of freshly cut firewood (and these numbers are similar in other states across the U.S.).
As you can imagine, this means burning freshly cut wood is very hard. When you try to burn fresh wood, the moisture must all boil away first, robbing you of energy that could have otherwise been turned into heat. In fact, burning a pound of fresh firewood with 0.43 pounds of water in it results in just 4,900 BTUs of heat energy.
After that same pound of fresh wood is seasoned, on the other hand, it consists of 0.83 pounds of dry firewood and just 0.17 pounds of water. Instead of netting a mere 4,900 BTUs of heat energy from the wood, you’ll get 8,600 BTUs of heat — an increase of over 75%.
Simply put, burning fresh, relatively wet wood is a waste of energy, firewood, and money. Seasoning your logs allows the moisture in them to evaporate, resulting in a cleaner, hotter, more efficient burn.
But how do you season firewood, then? Let’s take a look at the process step by step.
How to Season Firewood
Seasoning firewood isn’t too difficult, but it is a bit time-consuming. The seasoning process can be broken down into four basic steps:
- Splitting the wood
- Stacking the wood
- Covering the wood
- Storing the wood
The steps sound simple enough, but there are some subtle nuances to each of them. So, let’s dive a bit deeper into each one.
1. Splitting the Wood
If you’re buying firewood instead of cutting it for yourself, this step will likely already be done for you. If you’re splitting your own cordwood, though, it’s best not to store it in big, round logs, but rather to split it into fourths.
Seasoning firewood is all about exposing it to the open air to allow the moisture to evaporate naturally. Splitting the wood exposes more of its surface area, helping it to cure and season more quickly.
Split firewood is also lighter and quicker to load. After all, it’s easier to put split firewood into a wood stove or furnace’s firebox rather than a large, round log. Also, it’s much simpler to stack firewood that’s been split.
2. Stacking the Wood
After you’ve split your wood, the next thing to do is to stack it up. Aside from the convenience of keeping all of the wood in one place, stacking firewood allows air to circulate around it. As this air passes in and out of the stack, it pulls unwanted moisture out of the wood.
If you can, it’s best to stack the wood with the split side facing down. This prevents any falling moisture from finding its way between the bark of the wood and the wood itself — an inconvenience that will lengthen the seasoning process.
You should also stack the wood off the ground if possible, utilizing a firewood rack or a set of two-by-fours. Not only does elevating the wood prevent ground-level moisture from ruining the lower logs, but it also deters insects from finding their way into the stack.
3. Covering the Wood
Covering stacked firewood sounds easy enough. Just throw a tarp over the whole thing and call it a day, right? Well, it’s not quite that easy.
While you should cover the top of the firewood stack, you should leave the sides exposed to the open air. Covering the sides of the wood is actually detrimental to the seasoning process. It will trap moisture inside, all but guaranteeing the wood will never get as dry as it should.
For the same reason, you should try to keep the cover from touching the top of the firewood if you can (though admittedly, this can be a bit more difficult depending on the size of your firewood rack and how high you’ve stacked your firewood).
4. Storing the Firewood
The last step — storing the wood — is in some ways the easiest and the hardest. It’s easy because it requires no additional work on your part (provided you’ve done the first three steps correctly). It’s simply a waiting game.
It’s hard, though, because it can be tough to know how long to let the firewood season.
Generally, it’s best to let firewood season for at least six months, so be sure to plan well ahead of the heating season. In some cases, it may even be best to leave the stack for 12 months (though beyond this, you’ll start experiencing diminishing returns).
This six-to-twelve-month period allows time for moisture to evaporate properly from the stack. As long as the wood is piled up off the ground and it’s covered on top, it should dry nicely and be ready for you by the next heating season.
What Kind of Firewood Should You Burn?
Splitting, stacking, covering, and storing: following these four simple steps will transform wet, fresh wood into seasoned firewood that burns hotter and more efficiently.
It’s natural to wonder next, though, “What kind of firewood should I burn? Which species is best?”
While some species of firewood do provide more heat energy than others, the answer is complicated. It depends on which species of firewood is more abundant in your area, how much each species costs near you (if you’re purchasing wood), what species you have access to cut, etc.
In our guide, “Best Firewood: Top 10 Types of Wood Fuel to Burn,” we take a closer look at different species of firewood, including their weight, their ease of splitting, their heat per cord of wood, and much more. Take a look at it to discover which kind of firewood is best for you.
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