Firewood Moisture Calculator
Estimate firewood readiness from wet weight, oven-dry weight, meter reading, species, split size, seasoning days, relative humidity, stack airflow, and your target moisture.
Choose a real stack situation, then adjust the numbers for your shed, yard, or stove target.
These cards compare common firewood behavior in a well-spaced single-row stack.
| Species | Typical green MC | Drying speed | Density class | Meter correction |
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| Split size | Typical face | Drying factor | Best use | Planning note |
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| Condition | Factor | Moisture effect | Best practice | Risk |
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| Preset | Species | Days | Meter | Estimated MC | Status |
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Firewood moisture is that variable that determines how a fire burn. The moisture in firewood determines whether the fire produces smoke or heat. If a firewood has too much moisture in it, then the firewood will not burn well and will produce smoke that will fill the house.
Many individual attempt to burn firewood that has not yet dried, and many individuals only discover after they have stacked their firewood that the firewood was wet. There is various method for determining if firewood is wet. There should not be a reliance upon only one of these method, however.
How to Tell If Firewood Is Dry
One method is to simply touch the firewood; wet firewood will feel cool to the touch. Additionally, firewood will leave a damp mark on the concrete beneath it if it is wet. Using a moisture meter is another method of determining if firewood is wet.
However, the moisture meter may only measure the moisture in the outer shell of the firewood unless an individual create a fresh face on the firewood. The weight of the firewood can also be used to determine moisture levels in the firewood. Every pound of water that is released from firewood is one pound of weight that the firewood loses.
The species of firewood that is used will affect the drying capability of the firewood. For instance, hardwoods such as oak and hickory contain high levels of moisture and lose moisture from those piece of firewood slowly. Softwoods, like pine and poplar, lose moisture faster than hardwoods, but eventually reach a point in drying where the softwood do not provide much heat to the fire.
The size of the split on the firewood will also impact how fast the firewood dry. The smaller the split in the firewood, the more faster that split will dry compared to a large split in the firewood. Airflow is required for the firewood to dry.
Airflow allow moisture to leave the firewood through the ends and split faces of the firewood pieces. Should airflow be blocked from the split faces of the firewood, airflow will not aid in the release of moisture from the firewood. Covers can be used to keep rain from the firewood, but they should not block the airflow around the firewood.
Humidity also affects how fast the firewood will dry. High humidity will prevent moisture from leaving the firewood. High humidity levels will cause firewood located in damp areas of a region to take longer to dry than firewood located in dry areas of a region.
The size of the split in the firewood will create certain result in the fire. Small splits and kindling will dry quick, but are quickly gone during a fire. Large splits will retain heat longer during the fire, but the center of those splits will remain wet even when the outside of the split is dry.
For this reason, many individuals will keep two separate stack of firewood. One stack may contain large splits of firewood for daily use, and another stack will contain larger pieces of firewood for later in the week when those larger split of firewood can be used. Common mistake made with firewood include only using one method to determine moisture levels.
For instance, using a moisture meter on the bark side of the firewood will read the moisture levels on the split face of the firewood. The moisture meter may read that the firewood is dry, but the center of the firewood may be moist. Weighing the firewood is another mistake.
If an individual does not know the dry weight of the firewood species that is being measured, then the weight of the firewood will be inaccurate. The calculator combine measurements from moisture meters, weights, and environmental factor to provide an accurate reading of firewood moisture levels. When the moisture levels of firewood reach the target level, perform one final check of the firewood moisture.
Make a final check of a freshly split face of the firewood to ensure moisture levels in the firewood match the prediction made by the calculator. If the moisture levels of the firewood are still above the target level, allow the firewood to sit for another month. After another month of drying, the moisture levels will reach the target level of moisture in the firewood.
Using a tool to measure moisture levels remove the guesswork in the entire process. By removing the guesswork, individuals will not place wet firewood into the stove to burn.
