Humidity in wood and combustion problems

Humidity in wood and combustion problems

What happens when wood is damp

If the logs we use to light the fire are not well dried, we will notice that more dirt accumulates on the glass door and the firewood takes longer than usual to burn. In reality, this is not an advantage, because the ability to produce heat will be much lower than normal. In addition, the residues generated, such as soot or creosote or smoke, will be greater.

It should be noted that firewood always has a degree of moisture, so we cannot expect there to be absolutely dry logs. In fact, if there were, they would burn too quickly and would not be useful. When looking at what firewood should I use for the fireplace we will look for one with approximately 20 percent moisture.

Damp firewood is NOT wet firewood

“So, do I have to store the firewood somewhere away from the rain?”, you might wonder. In reality, the moisture in the wood and rain are different, although keeping firewood in a dry and protected place is recommended.
Firewood producers do not have a giant closet in which they store the logs. When the wood is dry and ready to use, at least 8 months after cutting it, it is left in the open air, so it can get wet due to rain. However, if it is placed near the fireplace for a few hours, it will have dried and will be ready to use.

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Even so, the most suitable time to buy and store firewood is during the months leading up to winter. August, September, or October is the time when experts purchase their logs for winter.

moisture in the wood,wet firewood
That’s why, instead of wet firewood, people usually talk about green firewood, which is firewood that has not been properly dried, either because not enough time has passed since it was cut or because it has not been handled properly. This is the firewood you should avoid, not one that has been wet due to rain.

Is there a way to quickly dry wet wood?

Yes, there are some ways to quickly dry wet wood, although you should keep in mind that drying wood too quickly can cause warping or cracking, but for firewood use, it’s not a problem. Here are some options to speed up the drying process:

  1. Forced air: Use a fan to circulate air around the wood, which will help evaporate moisture more quickly. Make sure the wood is well-supported and has space for air to circulate on all sides.
  2. Dehumidifier: Place a dehumidifier in a closed room with the wet wood. This will help remove moisture from the air, speeding up the drying process. It’s not the fastest option but it’s one of them.
  3. Heater: Use a heater to increase the temperature in the room where the wood is located. A temperature of around 25-30 degrees Celsius (77-86 degrees Fahrenheit) should be sufficient.
  4. Hairdryer: If you only have a small amount of wet wood, you can use a hairdryer to direct hot air onto the wood’s surface. Move it constantly.
  5. Oven: For small pieces of wood, it’s possible to dry them in an oven at a low temperature (below 100 degrees Celsius or 212 degrees Fahrenheit). Place the wood on a baking tray and leave it in the oven for several hours, checking its condition periodically. Be very careful if you choose this option, for safety reasons.
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Is dry wood better for fireplace combustion?

Yes, dry wood is better for fireplace combustion than wet or green wood. Dry wood has several advantages compared to wet wood:

  1. Higher heating power: Dry wood has a lower moisture content, which means it produces more heat per unit of volume when burned. Wet wood, on the other hand, has lower energy efficiency because some of the energy is used to evaporate the moisture instead of generating heat.
  2. Less smoke and soot: Dry wood produces less smoke and soot during combustion. Smoke and soot can accumulate in the chimney, which can increase the risk of chimney fires and require more frequent cleaning.
  3. Ease of ignition: Dry wood is easier to ignite than wet wood, as the moisture in green wood makes ignition difficult. Dry wood ignites faster and allows the fire to establish more efficiently.
  4. Less emissions: Dry wood emits fewer harmful gases and particles during combustion. Burning wet wood can release more volatile organic compounds (VOCs) and fine particles, which can have negative effects on air quality and human health.

When choosing wood to burn in a fireplace, it is important to select wood that has been adequately dried, with a moisture content of 20% or less. This will ensure more efficient combustion, with less smoke and soot and a lower environmental impact.

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How to store firewood to continue drying

If you buy a good amount of firewood, you will have enough for the whole year or even a little more. To optimize fireplace combustion, store it in a well-ventilated area. This way, it will continue to dry and lose moisture, promoting heat capacity and also helping to reduce gas emissions, since green wood can multiply this element by 3.