By Nicole King | September 19, 2023

Solar Kilns: An Effective Way to Dry Firewood Quickly

Two stacks of wood in frames wrapped with plastic.

Do you use firewood, either to heat your home during the winter or for campfires? Do you wish you didn't have to wait so long after cutting down a tree to use the wood? 

Then consider trying out the solar kiln, developed by Glen Holt, the Cooperative Extension Service Outreach Forester at University of Alaska Fairbanks. It is a simple method to accelerate the seasoning or drying process for firewood. 

"Seasoning" is the process of drying out wood to a moisture content of 20%. Wet or unseasoned wood will produce a lot of smoke when burned. 

To begin, split your wood into chunks. More surface area will allow the wood to dry out faster. Splitting the wood also breaks up the bark, which can keep moisture inside for longer. The standard drying method involves stacking the wood in a protected area or structure. It can take several months or longer for the wood to properly season using this method. 

Use wood pallets for the base of your solar kiln, this will keep the wood off the ground and will allow air to circulate through the bottom. Use 1x4s or 2x4s to build a frame for the walls. Attach clear plastic patio or greenhouse panels to the top.

Stack your split wood neatly inside. Cover the sides with 4 mil plastic sheeting. Leave a gap at the top and leave the pallet sides exposed. Hot air will flow through the stack, drying out the wood faster than in an enclosed woodshed.

Check the wood's moisture content with a moisture meter. When the wood is below 20% moisture content, it is ready to be stacked and stored in a standard woodshed. Be sure your wood is appropriately protected from the weather conditions and will stay dry throughout the year. 

A man wearing a hat and coat, holding a small camera. For more information, contact Glen Holt at ggholt@alaska.edu 

Wood stacked within an enclosed structure.
Wood stacked under an exposed structure
Wood stacked on a frame and covered with plastic.
Wood stacked on a frame with a clear plastic roof.
Wood stacked on a frame.
Several stacks of wood on frames covered in plastic with clear lids.
Two solar kilns: wood stacked on a kiln, covered with plastic, and a window open at the top to allow for air flow.
A solar kiln.
A gap between the plastic siding and the clear plastic roof.
Wood stacked on pallets with frames built around them.
A window between the plastic siding and the clear plastic roof allows for air flow.