Reading Time: 12 minutes – Editor’s Note – 12th July 2023
Our original article was published in January 2023 and provided a comprehensive guide to firewood moisture content and how it impacts burning. We have enriched the article with a working definition for firewood moisture content, a section on factors affecting the moisture content of wood for burning (seasoning and drying, storage and handling, climate & environmental conditions), more details about moisture meters, the consequences of burning wood when it is wet and a section about tips for managing storage.
There is a lot more to making a fire than many might realise. Some might consider all wood to be equal, but this is not the case. The success of your fire is determined by the type of wood you use but the condition of the wood is also vital. So, if you are looking to improve the way in which your fires perform, you might want to read on and learn all about how to obtain ideal firewood moisture content.
A working definition for firewood moisture content
Firewood moisture content refers to the amount of water present in wood, measured as a percentage of the wood's weight, often using a firewood moisture meter. It is essential to check firewood moisture content to determine the dryness or wetness of the firewood.
To check firewood moisture content is crucial because it directly affects its burning performance. Higher moisture content results in more difficult ignition, reduced heat output, and increased smoke production.
On the other hand, lower moisture content promotes efficient burning, higher heat output, and cleaner combustion. Achieving and maintaining the right moisture content in firewood is essential for optimal burning efficiency, heat production, and minimising environmental impact.
The importance of firewood moisture content
It does not matter where you have your fire, whether it is a campfire, a wood burning stove or a fireplace, ideal firewood moisture content is crucial. A crucial aspect of maintaining a fire is ensuring that the firewood has a low moisture content, this ensures more efficient burning. This is often the reason why people ready-seasoned firewood because kiln dried logs moisture content is perfect for creating a successful fire.
We are often asked “What is the ideal moisture content for firewood?” To ensure proper burning, moisture content of less than 20% is needed, which is something you see with kiln dried logs moisture content. When the content of moisture rises higher than 20%, it becomes increasingly difficult to burn the wood effectively.
Determining the content of moisture in firewood can be tricky, but there are methods for measuring it. One popular method is using a firewood moisture meter, which can be inserted into the wood to give moisture readings.
It is also important to note that firewood can dry out too much. If the moisture content is too low, the wood will burn too quickly and leave less heat energy. Therefore, it is important to find the right balance of dryness to ensure optimal burning.
A roaring fire relies on the right firewood to burn longer and hotter
Ideal firewood moisture content range for efficient and clean burning
Many fireplaces and wood burning stove-related problems can stem from burning wood with a high moisture level. Read any appliance manufacturers instructions and it will notify you of this. This can lead to difficulty lighting the fire, poor burning efficiency, lack of heat generation and smoke production. Additionally, burning wet wood may result in loud noises such as hisses or spitting as the fire works to remove the moisture.
The high moisture content in freshly cut wood, often referred to as “green wood”, can make it hard to burn effectively as more energy is required to dry out the wood before it can burn properly.
Green wood immediately after it has been felled
The amount of moisture in wood can vary depending on when it is harvested. Wood that is cut during winter often has a moisture content that is lower than wood harvested during the Spring months. This is crucial because ideal firewood moisture content of less than 20% is needed if it is to burn efficiently. This is commonly the kiln dried moisture content that we find in shop purchased wood.
To reach this moisture level, wood must go undergo the process of seasoning, which helps dry out the wood. If the firewood moisture content is higher when it is cut, it will take more time to become dry enough to reach a level that enables it to be used as firewood. To speed up the seasoning process, it is best to cut wood when it has the lowest moisture content possible.
Please note that seasoning wood could take a significant amount of time. Hardwoods may take as long as 2 years to become dry enough for use, while it can take a year to dry out softwoods.
Dried wood will always burn better than wet wood
What wood takes the longest amount of time to dry out?
Different types of firewood have varying drying times, depending on their moisture content and density. Oak and Hickory are hardwoods and require more time drying than softwoods like pine and spruce. Firewood efficiency is heavily dependent on choosing the best wood, with low moisture content. What is the ideal moisture content for firewood? Well, it is always below 20% as this is the legal requirement, the answer must be though “as low as possible”!
Hardwood
Hardwoods such as oak have a higher density, which means they are more difficult to dry out. The process can take up to 2 years or more, as they have around 30-40% of moisture within them. This is because it takes a lot more time for the water to evaporate from the wood. If you want to speed up the process, then you could opt to purchase firewood as kiln dried logs moisture content is perfect for fires. However, once seasoned, hardwoods are often considered the best firewood to burn as they burn longer and hotter than softwoods and have high firewood efficiency.
Softwood
Softwoods, on the other hand, have a lower density, which makes them easier to dry out. They typically take around 1 year to dry to the right moisture content of 20% or lower. Softwoods have a high resin content which makes them ignite easily, but they also burn faster than hardwoods and have reduced firewood efficiency.
Semi hardwoods
Semi-hardwoods like Maple, Ash, and Birch are in between hardwoods and softwoods in terms of density, and they take around 1-1.5 years to dry. They are known to be good firewood as they burn long, hot, and clean.
The drying time of firewood depends on the type of wood and its moisture content. Hardwoods take longer to dry, while softwoods dry faster. It is important to note that the drying time can vary depending on the location and storage conditions. However, getting it right will ensure that your firewood moisture content reaches the optimal level.
Kiln dried firewood is always a great alternative to seasoning wood yourself
Factors affecting moisture content of wood for burning
The best moisture content for firewood can be influenced by various factors that impact its drying and storage conditions; these are discussed below.
Seasoning and drying techniques
Proper seasoning involves allowing freshly cut wood to dry naturally over time, typically for a period of up to two years. Factors such as wood species, size, and environmental conditions affect the drying process. Techniques like splitting your own wood from your own trees, stacking it in a well-ventilated area, and protecting it from rain and excess moisture help facilitate effective drying and lower moisture content.
The kiln drying process for firewood involves placing the wood in a specialised kiln where temperature and humidity are carefully controlled. This removes moisture efficiently, resulting in dry and seasoned kiln dried firewood ready for use and no need for checking firewood moisture content.
Storage and handling practices
Storing firewood in a covered, well-ventilated area protects it from exposure to rain and excessive humidity, preventing moisture absorption. Properly stacked firewood allows air circulation, aiding in further drying. Avoiding ground contact and using pallets or racks helps prevent moisture absorption from the soil. Additionally, handling firewood with clean, dry hands and avoiding contact with wet surfaces during transportation and stacking helps maintain its moisture content.
Climate and environmental conditions
Regions with high humidity and rainfall tend to have higher moisture content in the wood. Similarly, storing firewood in damp or humid areas can increase its moisture content. Environmental factors such as proximity to water bodies, shaded areas, and prevailing weather conditions also affect moisture absorption. Understanding the local climate and environmental conditions is essential for managing ideal firewood moisture content effectively.
Signs that firewood is dry enough to use
If you pick fresh wood and look to use it right away, then this will not have the right firewood moisture content. With this in mind, what are the signs that the moisture content of wood for burning is suitable?
- The colour – If there is a brown colour to the wood then this is considered dry firewood. If it has a green tinge to it, then this is considered “green wood” or wet firewood, this green colour disappears as the wood dries
- The weight – Dry firewood is known to be light in weight and wet firewood will be heavier due to the additional moisture
- Appearance – A low firewood moisture content can be identified by a dry appearance, much like you see in kiln dried log moisture content. In contrast, wet wood will have a smoother appearance
- Condition – Dry firewood will have cracks and peeling while wet wood will have a softer bark
How to check firewood moisture content and its suitability for use?
Determining the dryness of firewood can be a tricky task, but with the help of a moisture meter, you can accurately check firewood moisture content. Small enough to hold in the hand, a firewood moisture meter can be used to determine the amount of firewood moisture content. When the device is held against the wood, it returns a reading, enabling you to determine the moisture level.
The importance of moisture meters
Most moisture meters have two metal pins that protrude from the top, which are inserted into the wood to check firewood moisture content readings accurately. Some newer models do not have pins as they use non-destructive technology to measure moisture content. The device will typically have a digital screen that displays a highly accurate reading of the moisture content of wood for burning.
Checking firewood moisture content with a firewood moisture meter
So, if you are looking to obtain the moisture content of firewood then a moisture meter is a great tool.
What happens if you burn wood that is wet?
If you burn wood that is wet, it will produce less heat and more smoke, leading to inefficient combustion and potential issues such as excess creosote buildup. Checking firewood moisture content is crucial to ensure optimal burning performance.
Energy Loss
When you burn wood that is wet, it results in energy loss as the fire is trying to turn the water into steam. This process takes a lot of energy and results in less heat being produced. Around 1,200 BTUs or British Thermal Units of heat energy are wasted when generating steam from water that weighs around a pound. On the other hand, dry firewood that has a 20% moisture content and weighs a pound will generate heat that is the equivalent of 7000 BTUs. This difference in efficiency highlights the importance of using dry firewood for optimal heat production as per appliance manufacturers instructions.
Wet wood can lead to health risks and problems with your chimney
Tips for managing storage
By following the tips below, you will effectively manage the moisture content of your firewood, ensuring optimal burning wood performance and a warm, efficient fire:
- Proper storage and protection from moisture - ensure firewood is stored in a dry and well-ventilated area, protected from rain, snow, and ground moisture. Use a firewood rack or elevate the wood off the ground to prevent moisture absorption
- Regular monitoring and maintenance of firewood supply - check firewood moisture content periodically using a firewood moisture meter. Aim for a firewood moisture content of around 15-20% for efficient burning. Rotate the woodpile regularly, using older, drier logs first to ensure a consistent supply of well-seasoned firewood
- Proper stacking and airflow - stack the firewood in a way that allows for proper airflow between the logs. Avoid stacking wood too tightly, as this can hinder drying. Consider stacking the wood in a crisscross pattern or using spacers to allow air circulation
- Covering the woodpile - use a waterproof cover or tarp to protect the stacked firewood from rain and snow while still allowing for airflow. Ensure the cover is secured to prevent it from blowing off in windy conditions
- Avoid stacking against exterior walls - stacking firewood against the exterior walls of buildings can lead to moisture transfer from the wood to the structure. Leave some space between the woodpile and walls to allow for airflow
Proper storage is essential to reduce firewood moisture content
Health Risks
Using wet wood can not only be less efficient, but it can also lead to health problems. This is why checking firewood moisture content, is so important. Wet wood will generate a lot of smoke which releases small particles as well as pollutants into the air. This can be harmful to those with respiratory issues. Additionally, when wet wood is burned, it can lead to a build-up of creosote in the chimney. This can increase the risk of a fire hazard as creosote is highly flammable. This happens as less heat is generated from wet wood, and this creates an accumulation of creosote on the chimney flue. It is important to use dry wood to avoid these hazards and to ensure the fire burns efficiently.
Firewood efficiency
The moisture content of firewood must be perfect for a fire to burn effectively, burn efficiently, and safely. Wood that contains a high moisture level will generate smoke in a fireplace, a wood burning stove, etc., This is harmful and dangerous. So, if you want a fire that burns for a long time, gives off the right heat and is safe, you should choose a hardwood that has the correct moisture level, as proven by a moisture meter. If you do not have the time to wait for the wood to season, our kiln dried logs moisture content will be perfect for a roaring fire, so you can always purchase ready-seasoned wood, directly from us!
How to contact Cozilogs
If you have any questions about purchasing dry wood logs with the best moisture content for firewood, get in touch. Cozilogs have a range of logs, which will improve your firewood efficiency. Please feel free to contact us through any of the following methods including how to check firewood moisture content to discuss the best products for you:
- Contact Information - https://www.cozilogs.co.uk/contact/
- Email us at sales@cozilogs.co.uk and
- Telephone calls - (01905) 954 736