Air Drying vs Kiln Drying

We are going to compare two methods used to dry lumber: air drying and kiln drying. Both methods have their advantages and disadvantages, and in a later blog post, we will go more in depth about the different types of kilns out there.

Air Drying Lumber

Air drying is the oldest and most traditional method of drying lumber. It involves stacking the lumber in a dry, well-ventilated area, such as a shed or under a shelter, where it is exposed to the natural air currents. Air drying can take several months to years, depending on the thickness and type of lumber being dried, the humidity level, and the weather conditions.

One advantage of air drying lumber is that it is a low-cost method. Since it does not require any specialized equipment, it can be done using simple tools, making it ideal for small-scale operations. Additionally, air-dried lumber is less prone to defects such as checking or warping, as the process is slower and more controlled. It also results in a more natural appearance of the lumber where more of the natural hues and colors are retained, which is highly sought after in certain applications such as furniture making.

However, there are also some disadvantages to air drying lumber. The process is time-consuming and requires a significant amount of space, as the lumber needs to be stacked in a well-ventilated area. Additionally, the lumber may be susceptible to insects, fungi, and other pests if not stored properly.  And there’s nothing worse than milling a bunch of lumber just to have a bunch of bugs eat it!

Kiln Drying Lumber

Kiln drying is a more modern method of drying lumber that involves using specialized equipment to dry the lumber more quickly and efficiently. There are several different types of kilns out there which we will explore more in a later blog.  But in general, the process involves stacking the lumber in a kiln and using heat, dehumidification, air flow, etc. (depending on the type of kiln) to remove moisture from the wood. Kiln drying takes significantly less time than air drying and can be completed in a matter of days or weeks, depending on the thickness and type of lumber being dried.

One advantage of kiln drying lumber is that it is a faster and more efficient process. It allows for more precise control over the drying process, resulting in more consistent and uniform drying of the lumber. Kiln drying also reduces the risk of insect and fungal infestations.  Molds need moisture to survive and the types of bugs that feed on wood only eat wood that is still full of water.  So when the wood has been dried much quicker in a kiln, there simply isn’t time for mold and insects to have their way with the lumber.

However, there are also some disadvantages to kiln drying lumber. It is a more expensive method as it requires specialized equipment, energy, and expertise to operate. The process may also cause the lumber to develop defects such as warping, checking, or splitting, as it dries more quickly than air drying.  And kiln drying tends to cause the wood to lose some of its natural color with the resulting wood having colors that are more dull or muted.  The exception to this would be a solar kiln, which uses sunlight to dry the wood and does so at a slower rate compared to other types of kilns.  Additionally, some of these kilns use a lot of energy and therefore are not friendly to the environment.

Conclusion:

In conclusion, both air drying and kiln drying have their advantages and disadvantages. While air drying is a low-cost, traditional method that results in high-quality lumber, it is a time-consuming process that requires significant space and is susceptible to pests. On the other hand, kiln drying is a faster and more efficient process that produces more uniform and consistent drying of the lumber, but it is more expensive and may cause defects in the lumber.

Here at Wildfire Lumber, we built our own solar kiln, because to us – this gives the best of both worlds!  It speeds up the process compared to air drying, but is completely safe for the environment and it still retains the natural color and beauty of the wood.