Why Is My Firewood Moisture Meter Reading Too High? Common Fixes

If your firewood moisture meter is reading too high, the good news is that the wood is often drier than the meter is telling you. Far more high readings come from testing the wrong way than from genuinely wet logs. A meter only measures the tiny spot between its pins, so where and how you push them in changes the number completely. This guide walks through the common mistakes that inflate a reading and shows you how to test firewood properly so you can trust the result.

The target you are aiming for is 20% moisture content or below, which is the level at which firewood burns cleanly and is now the legal standard for wood sold in small volumes in England. If your meter keeps showing 25%, 30% or more on wood you think is seasoned, work through the list below before you assume the logs are not ready.

1. You are testing the outside, not a fresh split

This is the number one cause. The outer surface and bark of a log behave differently to the inside. Bark insulates and traps surface moisture, and a face that has been exposed for weeks can be damp from rain or dew even when the core is bone dry. Either of these gives an artificially high reading.

The fix: split a log in half and immediately test the freshly exposed inner face. That freshly split centre is the only reading that reflects the true moisture of the wood.

2. The surface is wet from rain or dew

If your logs have been rained on, or you have brought them in from a damp store on a cold morning, surface moisture will inflate the reading even on a split face. A meter cannot tell the difference between water sitting on the surface and water bound in the wood.

The fix: test wood that has been under cover and is dry to the touch, and always split to a fresh, dry face just before measuring.

3. The wood is cold

Pin-type meters are calibrated to read correctly at around room temperature, roughly 20°C. Cold wood, straight from an unheated shed in winter, reads higher than it really is because temperature affects the electrical resistance the meter is measuring. This catches a lot of people out in the burning season.

The fix: bring a log indoors and let it reach room temperature for a few hours before testing, or use a meter with temperature compensation. Do not judge seasoned wood on a reading taken at near-freezing.

4. You are measuring the end grain or across the grain

Where you place the pins matters. Testing the cut ends (end grain) or pushing the pins across the grain gives unreliable, often high, readings. The ends dry and rewet faster than the body of the log, so they are never representative.

The fix: test across the middle of a freshly split face, with the two pins aligned along the grain, pushed in firmly so both make full contact. Avoid knots, cracks and resin pockets, which distort the reading.

5. The meter needs calibrating or has a flat battery

Cheap meters drift, especially after being dropped, and a low battery can throw the numbers out entirely. If readings look inconsistent or suspiciously high across lots of logs, suspect the meter, not the wood.

The fix: check the battery, and calibrate the meter if it has that function, at the start of each season. Testing a known dry offcut is a quick sanity check. If your meter is unreliable, our guide to the best firewood moisture meters in the UK and the difference between pin and pinless meters will help you choose a better one.

How to test firewood correctly, step by step

1. Bring a few sample logs indoors and let them reach room temperature.
2. Split each log in half to expose a fresh inner face.
3. Set the meter to a wood or generic softwood setting (fine for firewood screening).
4. Push the pins firmly into the middle of the fresh face, along the grain, away from knots.
5. Test several logs from different parts of the stack and take the average.

If the average is 20% or below, your wood is ready to burn. If it is genuinely higher after testing this way, the wood simply needs more seasoning time. Our guide on choosing a moisture meter covers the kit, and for the wider standard, Woodsure and the Ready to Burn scheme explains the 20% rule for firewood in the UK.

Frequently asked questions

Why is my moisture meter reading too high on seasoned firewood? Usually because you are testing the outside, the bark, or a rain-damp or cold surface rather than a freshly split inner face at room temperature. Split a log, test the fresh centre across the grain, and the reading almost always drops to its true, lower value.

Does cold wood give a higher moisture reading? Yes. Pin meters are calibrated for around 20°C, and cold wood reads artificially high because temperature changes the resistance the meter measures. Bring logs indoors to warm up before testing, or use a meter with temperature compensation.

Where should I put the pins on a log? Split the log and push the pins into the middle of the freshly exposed face, aligned along the grain, pressing firmly so both pins make full contact. Avoid the ends, bark, knots, cracks and resin pockets, which all give misleading readings.

What moisture level should firewood be? Aim for 20% or below, which is the point at which wood burns cleanly and efficiently and is the legal standard for firewood sold in small volumes in England. Above that, wood produces more smoke, less heat and more tar in your flue.

Could my moisture meter be faulty? It can. Cheap meters drift after being dropped, and a flat battery skews readings. If lots of logs read strangely high, check the battery, recalibrate if possible, and test a known dry offcut. If it stays unreliable, replace it with a better meter.