Firewood advice

Kiln dried vs seasoned firewood: what's the difference?

Both can burn well. The difference is how the moisture is removed, and whether you can trust it before you strike a match.

Last updated August 2026 · William Alexander Logs

Kiln-dried logs stacked and ready to burn from William Alexander Logs

What "seasoned" firewood actually means

Seasoned firewood is wood that has been left to dry naturally, usually stacked outdoors under cover, for a period of months to a couple of years depending on the species and how it was stored. Done properly, in a well-ventilated stack off the ground with the tops covered, seasoning works. The problem is consistency: a log seller's "seasoned" pile can range from genuinely dry to barely started, because there is no simple way to check a stack of logs by eye and no certification behind the word "seasoned" on its own.

What "kiln-dried" firewood means

Kiln-dried firewood is dried in a kiln at a controlled temperature over a set period, driving moisture out of the wood far faster and more evenly than air alone. The result is a batch of logs with a known, consistently low moisture content rather than a guess. All of our firewood is kiln-dried below 20% moisture and certified under the Woodsure Ready to Burn scheme (certificate WS721), so every bag meets the same standard, not just the logs on top of the pile.

Why the moisture content is the thing that actually matters

Whether wood is technically "seasoned" or "kiln-dried" is really just two different routes to the same goal: getting moisture content below roughly 20%. Above that, a fire has to burn off water before it can burn wood, which costs you heat, produces more smoke and tar, and is the main reason for a poor, smouldering fire. Below 20%, wood lights more easily, burns hotter and cleaner, and deposits far less tar in a chimney or flue. Kiln-drying simply gets you there reliably and consistently in every batch, rather than depending on how long a particular log happened to sit in a shed.

Is kiln-dried worth paying more for?

Kiln-dried logs are usually a little more expensive per bag than unverified "seasoned" logs, but you use fewer of them for the same fire because more of each log's energy goes into heat rather than driving off moisture, and you avoid the false economy of a cheap load that turns out to be wet, hisses and spits, and clogs a flue with tar. If you want a fire that lights first time and burns cleanly without a moisture meter and a guessing game, kiln-dried, Ready to Burn certified wood removes the uncertainty.

Quick questions

A few more questions.

Can seasoned wood be just as dry as kiln-dried? +
Yes, if it has genuinely been seasoned long enough, in the right conditions. The issue is that there is no easy way to verify it without a moisture meter, and quality varies a lot between suppliers and even within the same stack.
Does kiln-dried wood need any further seasoning? +
No. Kiln-dried, Woodsure Ready to Burn certified logs are ready to burn as soon as they arrive, provided you keep them dry until you use them (see our guide on storing firewood).
Why do kiln-dried logs sometimes cost more per kilo? +
The kiln-drying process itself costs energy and time, and the certification requires regular testing. You are paying for a guaranteed, consistent moisture content rather than an estimate.
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