To increase the efficiency of burning logs there is only one main element. Or rather the lack of one element! Water. We dry our logs by two main processes.
The first is time, and the second is by splitting the wood open to increase the surface area open to the air. There are four main advantages to dry logs:
- Improves storage capability.
(no mould or degrading) - Increase in energy density
(calorific value). - Decrease in transport weight.
- Reduction in ash and emissions.
In an earlier era it was normal practice to burn wet wood. Firewood was in plentiful supply and dry wood burnt too quickly in the huge open fires. And thus people from years ago became keen observers of how different types of unseasoned wood burned. Hence the old rhyme that ends “…But ash green, or ash old is fit for a queen with a crown of gold.”
The fact is, this is nonsense in the context of burning dry wood. When logs are fully seasoned, the differences all but disappear.
Wood Burning Stoves
Also, to run a modern closed appliance of today efficiently and with fewer maintenance issues, the wood must be dry. With wet wood you get a degrading of combustion efficiency, which means your fire produces a dense pall of smoke containing unburned tars and creosotes. The human response to an under-performing fuel is to over-run the stove which significantly increases heat-loss to the chimney.
If you persist in burning wet wood you will incur several penalties. Firstly you will burn more wood. Secondly, you foul up your chimney which produces a fire-hazard. Thirdly, over-running a stove shortens its life by subjecting it to excessive heat along the flue path. And fourthly, you lose control because the fire will go out or slumber unless you run it continuously at full throttle.
One useful check on the moisture content of your fuel, dare I say it, is to run your stove for a short while on a box of kiln dried logs. If the performance of the stove is transformed, then the wood you have is wet.