How to Test if Your Firewood Is Dry: A Moisture Meter Guide

Wood is a natural product, when a tree is freshly cut down, the logs it produces can contain up to 50% water by weight! This depends on species, but any fresh cut wood is unsuitable to burn immediately – unless you want a cooler, smoky fire that is. Whether you burn hardwood or softwood, a moisture meter can help you burn efficiently.

Seasoning reduces the moisture content of logs

People season firewood logs before burning to reduce the moisture content. Lower moisture means that less energy is used to evaporate the moisture from the fuel, giving you more warmth from the same volume. A bag or crate of seasoned logs will be lighter than the unseasoned equivalent. This is why logs are sold in units of volume and not weight.

While traditional seasoning can take many months to even years, kiln-drying can reduce the moisture content of logs to acceptable levels within weeks. Either method is fine, so long as the wood has a moisture level of 20% or (ideally) less before burning.

How do I find out the moisture content of my logs?

If you are seasoning your own wood, a moisture meter can save you time and frustration by giving you an estimate of your firewood’s moisture content. Your logs might be ready earlier than expected meaning you can burn them sooner. Conversely they might not be ready at all, in which case you will leave them to season a bit longer.

If you are buying wood that’s already seasoned or kiln-dried, a moisture meter can give you confidence that the logs you have bought are as dry as advertised. You’ve gone to the expense of paying for a premium product so that you can burn efficiently, create less pollution and save time and space otherwise spent seasoning logs yourself – it makes sense to verify the delivery matches what you have paid for. In England, it is illegal to sell logs as Ready to Burn if they have a moisture content above 20%.

How to take an accurate reading

Taking a few logs from multiple places in your store, split them with your favourite axe, maul or splitter, then place the moisture meter’s probes on the freshly split inside surface of the log in various places. The average/mean reading taken will give you a good estimate of the moisture content of your logs. The more readings you take will give you a more accurate picture, but typically you can get a good indication from 3-4 random logs.

It's worth buying a moisture meter

It’s much easier to burn dry logs, they create less smoke and pollution and give you more valuable heat. Buying a moisture meter and knowing how to use it can save you money, protect the environment and save you the frustration of trying to light a fire with wet wood. Happy testing!