What Moisture Should Firewood Be? Guide to Burn-Ready Logs

When it comes to building the perfect fire—whether in a wood-burning stove, fireplace, or outdoor fire pit—the moisture content of your firewood is absolutely critical. If you’ve ever struggled with smoke, poor heat output, or logs that simply won’t catch alight, chances are you’re burning wood that’s too wet.

So, what moisture should firewood be? In this definitive guide, we’ll explain everything UK homeowners and firewood users need to know—ideal moisture levels, how to check them, and the key differences between kiln-dried and naturally seasoned logs.

Ideal Moisture Content for Firewood: The Magic Number

The ideal moisture content for firewood is 20% or less. In the UK, this threshold is important not just for performance but also to comply with legislation under the Ready to Burn scheme, which requires firewood sold in small volumes to meet this standard.

Here’s why 20% moisture matters:

Better combustion: Drier wood burns more efficiently, producing more heat and less smoke.
Less creosote build-up: Wet logs lead to creosote deposits in chimneys, increasing fire risk.
Lower emissions: Burning dry wood significantly reduces harmful particulates and carbon output.
More cost-effective: You’re not paying for water weight or wasting energy evaporating moisture.

Kiln-Dried vs Naturally Seasoned Firewood: What’s the Difference?

There are two main ways to reduce the moisture content of firewood: natural seasoning and kiln drying. Let’s break down the pros and cons of each method:

Kiln-Dried Firewood

Kiln drying is a controlled process where firewood is baked in a purpose-built chamber at high temperatures. It rapidly reduces moisture to below 20%—often as low as 10–15%.

Pros:

Consistent low moisture content
Ready to burn immediately
Cleaner burn, more heat, less smoke
Less risk of mould, pests or rot

Cons:

Higher upfront cost
Uses energy to dry (though many UK suppliers use renewable biomass kilns)

Naturally Seasoned Firewood

Seasoned firewood is air-dried outdoors over several months—or even years—until the moisture content drops below 20%. Logs are typically stacked in a dry, ventilated location.

Pros:

Environmentally passive drying process
Can be cheaper if you prepare it yourself

Cons:

Takes 6–24 months to season properly
Moisture content varies
More risk of decay or mould if stored incorrectly
Not guaranteed to meet Ready to Burn standards unless tested

How to Measure Firewood Moisture

Wondering if your logs are dry enough? The best way to check is with a digital moisture meter—a small hand-held device that probes into the wood and gives a real-time reading.

Tips for accurate testing:

Split the log: Always measure the freshly split face, not the bark or end grain.
Test multiple pieces: Readings can vary between logs, even in the same pile.
Aim for under 20%: Anything above this may produce smoke, creosote and inefficient heat.

If you’re buying firewood, look for Ready to Burn certification which guarantees it meets legal moisture requirements.

Why Moisture Matters When Buying Firewood

If you’re purchasing firewood in the UK, choosing low-moisture logs isn’t just about convenience—it directly impacts your comfort, wallet and safety.

With kiln-dried firewood, you get:

Instant usability, no drying time
Better fuel economy
Cleaner flue and chimney
Full compliance with UK smoke control regulations

Many trusted UK suppliers now exclusively sell kiln-dried hardwood logs in crates or bulk bags, ensuring consistent quality and moisture control.

Storing Firewood to Keep It Dry

Even the driest logs can reabsorb moisture if not stored properly. Follow these simple tips:

Keep logs off the ground (use a log store or pallet base)
Cover the top, but allow for side ventilation
Avoid airtight containers or plastic wraps
Store logs in a dry, sheltered area like a woodshed or garage

Final Thoughts: What Moisture Should Firewood Be?

To answer the question directly: firewood should have a moisture content of 20% or less to burn efficiently, cleanly, and safely. For best results—and the least hassle—kiln-dried logs offer unbeatable consistency, especially during the damp UK winter months.

If you’re serious about heat output, stove longevity, and clean combustion, don’t settle for soggy logs. Choose premium kiln-dried firewood with verified moisture content and keep your home cosy all season long.

Order High-Quality Kiln Dried Firewood Online

Our kiln dried logs are prepared for performance — low moisture, strong heat output and reliable ignition every time. Whether you’re planning ahead for winter or simply topping up, shop our range today and have premium firewood delivered to your home.