There are a number of things to learn about as a new wood-burning stove owner. There will inevitably be a number of considerations that will come up regarding fuel source, the mechanics of your furnace, seasonal considerations, and a number of others.
How does my furnace really produce heat?
Heating with wood is based on the principles of combustion. Fuel (the wood), air and heat are combined to create a series of reactions that result in a source of heat for your home, shop, or facility.
There are three stages of combustion. The first is where the wood begins the burn, continues to increase in heat, and change composition to charcoal that acts as an ignition for larger and later wood to be added.
The second stage begins when any residual moisture has been pulled from the wood in the creation of charcoal, and where the wood comes up above 540º F. There is a primary temperature of 540º to about 900º, and the second from 900º up to 1100º where 60% of the woods potential heat is found (through a process of releasing gasses) Depending on the fuel source (prior numbers are for wood burning), you can reach up to 2000 degrees when using pellets or wood chips.
The third stage begins when the gases are driven from the wood and the carbon or charcoal continues to burn at a long, low rate of heat output. This stage is important for efficiency, as a well established charcoal bed will burn for a long time, allowing fire to last throughout the night.
Why won’t my fire start/how do I keep my fire burning efficiently?
If you have trouble starting your fire, or if you have trouble keeping your fire going, you are probably using unseasoned firewood. Green or unseasoned wood (internal moisture greater than 20%), will smoulder if it lights, will not put out heat and will burn poorly.
This is due to the moisture content being high, which requires additional energy to evaporate, and also causes creosote build up at an accelerated rate. One fresh-cut cord of oak may contain enough water to nearly fill 6, 55 gallon drums. The moisture content in the wood determines how much heat the fire puts out, and how much creosote will build up in your chimney.
Depending on when the wood was cut down and split, softwoods like pine, tamarack or spruce might be dry enough within 3 to 6 months to burn efficiently if stacked where the sun and wind can reach them for seasoning. 6 months is not enough for most hardwoods, especially oak. As far as quality is concerned, oak is great wood. Oak is very dense wood. It burns extremely hot, and for a long time.
A mix of good oak and softwoods is your best bet for a longer, efficient burn. Use the softwood during the day when you are near the stove / fireplace to refill it, and the oak overnight for prolonged heat and embers in the morning.
How do I know if the wood is seasoned?
Looks aren’t everything. This statement rings true for determining whether your wood is seasoned. Seasoned wood may look darker, or dingy, or grey compared to green wood – but if you split a piece of seasoned wood – it should be white on the inside. It may seem brittle, or gnarly, and will be rough unfinished wood. If it’s split in quarters, seasoned wood has cracks running through each piece, and a lot of little cracks on the inner rings at the ends of each piece. Tap two pieces of wood together…seasoned wood gives a sharp, resonant sound, like a baseball bat or two 2×4’s coming together.
Unseasoned wood on the other hand is either green or has yellow properties. This is due to its moisture content. Unseasoned wood makes a dull sound when hit together. Unseasoned wood also has very few cracks, and it has a fresh looking centre because it is actually still damp. When firewood is very fresh, the bark will be tightly attached.
When is the right time to buy firewood?
Depending on when the firewood needs to be used, buying firewood year round is possible. Here are some considerations when planning your firewood purchases:
When purchasing wood for immediate use, make sure it’s fully seasoned. You won’t be sorry if you spend a little more money, just to make sure that you enjoy trouble free firewood. Fully seasoned firewood will burn clean, burn longer and reduce creosote residue in your chimney.
The best firewood is 1-3 years old. When wood gets over 5-6 years old, it does start to deteriorate. If your fuel of choice is firewood, purchasing (whether green or seasoned) 1 full year in advance allows the material time to cure for a clean efficient burn when needed.
Green or unseasoned wood is not something to be avoided, as long as you give it enough time (and the right conditions) before it’s needed as a fuel source. Green wood can typically be found at a better price, but you need time to reduce the moisture content below 20% for an efficient burn.
Fully seasoned wood at a great price does come along, but is often not advertised, because the serious wood burners already know where to go. If you are a first time wood burner, either buy dry, split softwoods, or hunt down really dry, cracking hardwood.
Is burning firewood considered renewable energy?
All the renewable sources of energy are considered clean forms of energy, including firewood which is a form of biomass. Burning wood rather than gas or oil is good because the resource is renewable. It is essentially solar energy — sunshine trapped by photosynthesis into the tree’s tissue is released as heat in your home, so there’s no net increase in heat at the earth’s surface.
An efficient fireplace releases mostly water vapour and carbon dioxide. The latter is a factor in global warming, but in the case of burning wood, no more so than if the tree had died in the forest and decomposed there. By contrast, burning coal, gas or oil releases CO2 that would otherwise have remained trapped underground. While it is true that burning firewood can release particulates into our atmosphere, these particulates are for the most part organic, which clean the air by binding with inorganic pollutants in the atmosphere.
These points cover the mechanics of your furnace, fuel source of choice and their environmental impact, and we hope that these have either clarified points of uncertainty, or have sparked other questions to seek out answers to!
We are passionate about what we do and would love to hear from you on additional topics you’d like us to research and discuss!
For more information on wood as a fuel source visit https://www.firewoodmanitoba.ca/faqs-2/Back to all posts