Published on 4 November 2025
Posted in Firewood
Wet wood is the single biggest reason fires perform poorly. It smoulders instead of burning, blackens your stove glass with tar, and sends most of your heat up the chimney.
The frustrating part? Most people don’t realise their wood is too wet until they’re trying to light it.
A moisture metre removes all doubt. This simple tool tells you exactly whether your firewood will burn well or disappoint. More importantly, it shows you when wood that looks dry on the outside is still soaking wet inside.
Moisture content is simply the percentage of water in your wood compared to its total weight. When you burn wet wood, your stove wastes energy boiling off water before any real heat reaches your room.
The UK’s Ready to Burn standard sets 20% as the maximum acceptable moisture level, and for good reason. Wood below this threshold ignites easily, burns efficiently, and produces minimal smoke.
Above 20%, you’re fighting a losing battle, poor heat output, excessive smoke, and dangerous creosote buildup in your chimney.
Even properly dried logs can absorb moisture if stored badly. Rain, damp air, or ground contact can ruin months of seasoning in weeks. This makes a moisture metre essential, whether you’re buying kiln-dried logs or seasoning your own.
Most affordable moisture metres use two metal pins that you push into the wood. The device measures electrical resistance between these probes. Since water conducts electricity far better than dry wood fibres, the metre can accurately calculate the moisture percentage.
Getting accurate moisture readings isn’t complicated, but it does require proper technique. Follow this method and you’ll know exactly what you’re dealing with.
This is crucial. Never test the outside surface of a log or its bark. Wood dries from the outside inward, meaning the exterior might read bone-dry whilst the core remains saturated. You need to know the moisture content where it actually matters, inside the wood.
Take one log from your stack and split it completely in half. This exposes the fresh internal wood that genuinely represents the log’s moisture level.
Yes, this means you’re sacrificing one log per test, but considering you might be testing an entire winter’s fuel supply, it’s a sensible investment.
Even a thin film of surface water from rain, condensation, or snow will dramatically skew your readings. Use a dry cloth to wipe the freshly split face, removing any visible moisture. If your wood has been sitting outside in wet weather, ideally, bring a sample indoors and allow it to reach room temperature before testing. Frozen wood cannot be accurately measured.
Position your metre so the pins will penetrate across the wood grain rather than along it, ideally in the centre of the split face. Push firmly until the pins are embedded at least halfway into the wood. Many people make the mistake of tentative, shallow insertions. You want those probes properly seated in the wood’s interior, not just tickling the surface.
Avoid knots, cracks, or any visibly decayed areas, as these can produce unreliable readings.
If your pins keep bending (a common complaint with cheaper metres), you may need to apply more force or pre-drill tiny pilot holes, though quality metres shouldn’t require this.
Once the pins are firmly embedded, activate the metre and wait a moment for the display to stabilise. Most metres show results within two or three seconds. Note the number displayed; this represents the moisture content as a percentage of the wood’s total weight.
Professional wood suppliers and auditors don’t rely on a single reading, and neither should you. Select three or four logs from different areas of your stack, particularly if you’re testing a large delivery or wood that’s been stored in varying conditions. Split and test each one, then calculate an average.
This approach accounts for natural variation and gives you confidence in your assessment. If all your readings cluster around 15-18%, you’re golden. If they’re scattered wildly, you’ve likely got inconsistent seasoning that needs attention.
Moisture metres display percentages, but what do these numbers mean in practical terms?
| Moisture Content (%) | Wood Condition | Performance When Burning |
| 0 – 14% | Exceptionally dry (often kiln-dried or aged for several years) | Ignites instantly and burns extremely efficiently. Produces maximum heat with minimal smoke. Ideal for all indoor and outdoor fires. Some worry wood can be “too dry,” but this is rarely an issue for domestic use. |
| 15 – 18% | Ideal moisture range (properly seasoned or kiln-dried) | Burns hot and clean with excellent efficiency. Minimal smoke and soot buildup. Provides strong, consistent heat output. |
| 19 – 21% | Borderline, nearly ready, but not optimal | It will burn, but less efficiently. Produces slightly more smoke and lower heat output. May struggle with longer overnight burns. |
| 22 – 25% | Damp or insufficiently seasoned wood | Difficult to light and maintain. Produces excessive smoke and creosote buildup. Wastes energy and wood volume. |
| 25% + | Wet or freshly cut (“green”) wood | Smoulders, creates thick smoke, and may extinguish fires. Generates minimal heat and heavy creosote deposits. It can damage chimneys and stoves over time. |
Even with a reliable metre, poor technique produces poor results. Watch out for these frequent errors.
Don’t just press the metre against the bark or the outer surface; it dries faster than the core. The inside of the log can be up to 15% wetter, giving you a false impression that the wood is ready to burn.
Always split the log and test the freshly exposed inner wood.
Surface water from rain, snow, or frost will distort your readings. Likewise, frozen logs can’t be measured accurately.
Bring a sample indoors, let it reach room temperature, and make sure the surface is completely dry before testing.
Bent, corroded, or blunt pins reduce accuracy over time. Inspect and replace the probes when needed, and check your metre’s calibration regularly using the manufacturer’s guide.
A single log doesn’t represent the whole stack; moisture varies between pieces. Test several logs from different parts of your pile and average the results for a true picture.
Many metres have settings for different materials (like plasterboard or construction timber). Using the wrong mode gives meaningless results. Double-check your metre is set to the correct “wood” or “firewood” mode before testing.
If there’s one thing your moisture metre will confirm, it’s that not all firewood is created equal. At The Log Dog, we take the uncertainty out of wood burning by supplying premium kiln-dried hardwood logs that are consistently below 20% moisture content, ready to burn the moment they arrive. So if you don’t want to have to test your own wood, let us supply you with ready to burn firewood.
Our logs are carefully sourced, precisely dried, and quality-checked to deliver the clean, efficient fires your home deserves. Whether you’re heating with a wood stove, open fire, or outdoor fire pit, you can depend on us for perfectly prepared logs that ignite easily and burn beautifully.
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No more frustration with damp, smoky wood that refuses to burn. With The Log Dog, you’ll enjoy hotter fires, cleaner chimneys, and a warmer home, without the hassle of guesswork or last-minute scrambles for decent firewood.
Order your kiln-dried logs today and experience the difference properly prepared firewood makes. Call us at 01295 256 436 or browse our website to find the perfect firewood package for your home, and stay warm the smart, sustainable way this winter.
Test each new delivery or batch you prepare yourself if you haven’t got a ready to burn guarantee. Once you’ve established that your storage methods work well, you can reduce frequency, but always verify before the burning season begins.
You’ll get readings, but they’ll be artificially high due to surface moisture. Wait for the exterior to dry, or better yet, bring a sample inside to room temperature first.
The moisture content is what matters, regardless of species. However, some metres have species correction features because different woods have slightly different electrical properties. For basic firewood testing, this rarely makes a practical difference if you’re simply checking against the 20% threshold.
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