Are you thinking of stocking your woodpile with wet wood instead of dry or seasoned wood? You’re probably wondering why wet wood is cheaper and more readily available. Naturally, you’re suspicious and want to know if there’s a catch.
You can burn wet wood, but it’s less efficient than burning seasoned wood. That’s because wet wood has significant water content. When lit, the energy generated burns off this water instead of producing heat. Wet wood also produces excessive smoke and creates creosote deposits.
The money-saving idea of buying wet wood doesn’t sound so good now. But, you’re probably wondering how bad it can be. Well, that’s what you can find out below.
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Wet vs. Seasoned Wood: What’s the Difference?
First, let’s understand what we’re talking about by looking at the difference between wet wood and seasoned wood.
Depending on the species, trees contain a significant amount of water, exceeding the dry weight. The water content is what makes wood from a living or recently felled wet tree wood.
Once you cut and split a log from the tree, exposure to the air starts a drying process. The water loss reduces the weight of the wood and shrinks it. When the water content is 20% or less, this is seasoned wood.
So, it’s the water content that distinguishes wet wood from seasoned wood. In summary, seasoned wood has gone through a drying process to remove most of the water.
This wood drying process can take months if done naturally. If you need to dry out firewood yourself, the following video may help:
A speedier process is kiln-drying, which can take a matter of days.
Even if you’re buying seasoned wood, always check the water content. It’s easy to do using a moisture meter. For example, this General Tools MMD4E Digital Moisture Meter is inexpensive and easy to use.
The demonstration in this video proves how easy it is to use a moisture meter:
Whether you dry wood naturally or buy it kiln-dried, you can understand why seasoned wood is more expensive than wet wood.
While wet wood will burn, the problem with burning it is down to this water content. Let’s look at these issues now.
Wet Wood Produces Excessive Smoke When It Burns
You’ll find that you can get the wet wood lit, though it might take time. But the real issues arise once it’s burning. It’ll produce a lot of thick smoke, significantly more than if you burn dry wood.
Smoke contains PM2.5 particles, which can cause lung damage. So, in excessive amounts, the smoke that your fire generates becomes an environmental and health hazard. Countries are starting to take heed. For example, in England, there’ll be restrictions on using wet wood for fuel from 2021.
The following video shows how the smoke produced by burning wet wood in a wood-burning stove leaks back into the room. It doesn’t take much to imagine how bad it would be if you were to burn wet wood in an open fireplace in your home.
Wet Wood Produces Less Heat Than Seasoned Wood
As discussed above, wet wood has a high moisture content. When it’s lit, much of the energy it produces is spent boiling off that water content. Consequently, less energy gets converted to heat. This video demonstrates the fact well:
So, burning wet wood is less efficient than burning seasoned wood. You’ll know your wood is wet if it sizzles and drips when you burn it, as shown in this video:
Although wet wood is heavier than seasoned wood, giving you the impression that wet wood has more substance to it, don’t let that fool you. The weight is from the moisture content.
The upshot of this is that wet wood burns less efficiently than seasoned wood. So, wet wood may cost less to buy, but it’s a false economy.
The heat from wet wood is less than you get from seasoned wood, So, you’ll likely find yourself topping up your fire more often than if you burn seasoned wood.
Burning Wet Wood Causes Creosote Build-Up
When you burn seasoned wood, the oils in the wood vaporize into volatile carbon-rich gases. These gases mingle and react with gases in the smoke and oxygen, combusting to produce more heat. Exactly what you want from your fire.
Temperatures in a fire fuelled with seasoned wood can go up to 1225°F (663°C) or more. With this degree of heat, the waste by-products can rise up and escape through the chimney or flue.
As you’ve seen, burning wet wood produces less heat because the energy is wasted in boiling away the excess moisture. So, there’s insufficient heat to combust the carbon-rich gases.
Instead of combusting to produce more heat, those gases travel up the chimney in the smoke produced by burning wet wood. This gas-smoke mixture is at a temperature of only 212°F (100°C), the water’s boiling point.
As the smoke moves up the chimney, it cools the chimney down. With the temperature below 250°F (121°C), the gases in the smoke condense into creosote instead of escaping out the chimney.
Over time, this condensate solidifies and forms a nasty sticky residue of creosote on the chimney’s inner walls. But this isn’t just a horrible mess. Creosote is highly flammable. It can cause chimney fires if it’s left to build up.
Even if you manage to avoid a chimney fire, the creosote build-up contains caustic compounds that can damage your chimney or flue. So, it’s vital to remove it, and that will cost you.
So, while you can burn wet wood, you’re probably going to want to think long and hard before doing so. Let’s summarize why:
- The smoke from burning wet wood contains lung-damaging pollutants. That makes wet wood as a fuel an environmental and health hazard.
- Wet wood produces less heat, so it’s less efficient than burning seasoned wood. While it may cost less to buy, you’ll probably use more of it to achieve the level of heat you want.
- The lower temperatures produced by wet wood cause creosote deposits in your chimney. Creosote build-up is a fire hazard and damages your chimney.
There should be no smoke with your wood fire. If there is, you’re probably burning wet wood, with all the issues that might entail.