What is seasoned firewood, and why does it matter?

You load the firebox, hold a match to the kindling, and wait. The fire catches, then sputters. The wood hisses, steam creeps from the cut ends, and the glass fogs with smoke. An hour later the room is still cold. Nine times out of ten, the problem is the wood rather than the heater.  

Seasoned firewood is wood that has been dried until it holds very little water - under about 20% moisture. That single number is the whole game. Get your wood below it and your heater lights easily, burns hot, and stays clean. Stay above it and you fight the fire all night. A good wood heater is built to burn Australian hardwood cleanly, but even the best heater can only work with the fuel you give it.

What is seasoned firewood?

Seasoned firewood is wood that has dried out long enough for most of its water to escape. Freshly cut wood - often called green wood - can hold up to half its weight in water. All that moisture has to boil off before the wood will burn properly, and boiling it off steals heat that should be warming your room.

Moisture content is simply the share of the wood's weight that is water. Seasoned firewood sits below about 20%, and the sweet spot is around 15% to 20%. At that level the wood lights quickly, burns hot, and gives a clean flame instead of a smoky smoulder. Above 20%, the fire turns sluggish and hard to control. That is why every clean-burning fire starts with dry wood.

How long does firewood take to season?

How long firewood takes to season depends on the species and where you store it. As a rough rule, dense Australian hardwoods take far longer than lighter timbers.

Most of our best firewood is hardwood - red gum, ironbark, box and sugar gum. These woods are heavy and slow-drying, so they often need around 12 months or more to season fully. In humid, shaded, or coastal spots the same wood can take longer again. Lighter hardwoods and softwoods hold less water and dry faster, sometimes in a few months. Splitting the wood and stacking it with room for air will always speed things up.

In southern states like Victoria, the easiest approach is to split your wood in late winter or early spring. That gives it the hot, dry summer to do most of the drying before the next cold snap. Melbourne's wet winters make timing matter - wood cut too late simply will not be ready when you need it.

A rough guide to drying times

Firewood type	What it's like	Rough drying time
Dense hardwood (red gum, ironbark, box)	Heavy, slow-drying, long steady burn	Around 12 months or more
Lighter hardwood (some gums)	Medium weight, moderate burn	Around 6 to 12 months
Softwood (pine, cypress)	Light, quick to catch, fast burn	Around 3 to 6 months

Treat these as a guide. Drying times shift with climate, how the wood is split, and how well air moves through the stack. For more on which species burn best, see our guide to the best types of wood to burn.

How can you tell if firewood is dry?

You can tell if firewood is dry from a few simple signs you can check by hand. None is perfect on its own, but together they give you a good read.

• Weight: dry wood feels noticeably lighter than green wood of the same size.
• Colour: it fades to a dull grey or pale tone instead of fresh, bright timber.
• Sound: knock two pieces together. Dry wood gives a sharp, hollow crack; wet wood makes a dull thud.
• End grain: look for cracks and splits spreading out from the centre of the cut ends.
• Bark: on seasoned wood the bark is often loose, flaking, or already gone.

For a definite answer, use a moisture meter. This is a small tool with two metal pins that you press into the wood to read its moisture content. They cost around $20 to $40 at most hardware stores. Split a log first and test the fresh inside face, because the outside dries faster than the core. A reading under 20% means it is ready.

A moisture meter takes the guesswork out of it: under 20% and you're ready to burn.

If you do not own a meter, there is an old test that still works. Light a single piece outside. If it hisses, steams, or struggles to catch, the moisture content is still too high.

What does burning wet wood cost you?

Burning wet wood costs you heat, cleanliness, and safety every time you light it. The downsides stack up quickly.

• Less heat: the fire spends its energy boiling off water instead of warming the room, so the heat output drops.
• A harder, smokier fire: wet wood is slow to light and slow to get going, and it smoulders rather than burning with a clean flame.
• More smoke outside: that smoke drifts into your yard and your neighbours'. Australia's wood heater emissions standard, AS/NZS 4013, sets a limit of 1.5 grams of particles per kilogram of wood burnt, but real-world smoke is driven far more by wet wood and how the heater is run.
• Creosote in the flue: the smoke leaves a sticky, tar-like residue called creosote inside the flue, the metal pipe that carries smoke out of your home. A heavy build-up is a genuine fire risk and is best cleaned out by a professional.
• A dirty heater: wet wood blackens the glass and coats the firebox, so you spend more time cleaning and less time enjoying the fire.

None of this means wood heating is messy or difficult. A modern heater burning dry wood runs clean and hot. The mess comes from the fuel, so the fix is in your woodpile.

Is seasoning the same as storing firewood?

Seasoning and storing firewood are two different jobs, and mixing them up is a common mistake. Seasoning is the drying process that brings green wood down below 20% moisture. Storage is what keeps already-dry wood dry so it stays ready to burn.

Even perfectly seasoned wood will soak up moisture again if it sits on wet ground or under steady rain. The basics are simple: keep the stack off the ground, leave room for air to move through it, and cover the top while leaving the sides open. We cover stacking and covering in more detail in our guide to storing firewood at home.

Frequently asked questions

Can you burn green or unseasoned wood?

You can light green wood, but you will not enjoy it. It is hard to start, gives off little heat, and produces heavy smoke and creosote. In a pinch, mixing in a little drier kindling can help a sluggish fire along. As a regular fuel, though, green wood is not worth the trouble or the flue cleaning it leads to.

Is kiln-dried firewood the same as seasoned firewood?

The end result is much the same: low-moisture wood that burns well. The difference is the method. Seasoning dries wood slowly in the open air over months, while kiln-dried wood is dried quickly in a large oven. Both are fine to burn as long as the moisture content is under 20%. Kiln-dried wood usually costs more because of the extra processing.

Can firewood be too dry?

It can, though it is uncommon in most Australian homes. Wood much below 15% moisture burns very fast and can be harder to control, which wastes fuel. The sweet spot is around 15% to 20%. In our climate, well-stored wood rarely dries past that point on its own.

How much does a moisture meter cost?

A basic firewood moisture meter costs around $20 to $40 at hardware stores. It is one of the cheapest tools you can buy for your heater, and it takes the guesswork out of knowing when your wood is ready. Press the pins into a freshly split face for the most accurate reading.

Get the most from your heater

Dry wood is the simplest upgrade you can make to your fire. Get your firewood under 20% moisture and a good heater will reward you with a hot, clean, long-lasting burn all winter.

If you want help choosing a heater that suits your home, or advice on getting the most from the one you already have, talk to our team. Every Ultimate Fires wood heater is Australian-made and built to burn our local hardwoods well. You can see the full range and ask your questions in person at our showrooms in Dandenong, Epping, Geelong, Ballarat, Adelaide, and Perth.