THE ART AND SCIENCE OF WOOD FUEL

Any type of wood will burn, but not all wood burns the same.
Different species have very different energy values (calorific values), moisture contents, and burn characteristics — all of which affect the heat your wood burning stove delivers to the room.
Hardwoods such as oak, ash, beech and hornbeam burn longer and steadier, storing more energy per log.
Softwoods like pine, spruce or fir ignite easily and burn hot, making them ideal for kindling or reviving a fire.

A log of oak the same size as a log of soft pine will deliver almost twice the heat because of its density.

Sourcing and preparing the right wood is the foundation of clean, efficient burning.
But it’s also part of a much bigger picture — the difference between local stewardship and industrial exploitation.

The logs grown in our hedgerows, forests, gardens and streets were planted by our ancestors to serve the people and wildlife who live among them.
Yet today, local communities compete with corporate biomass schemes, taking whatever they can in order to get paid.

The people are increasingly being left to imported logs shipped across the world, processed and dried by machines that burn more energy than they save.

The most ethical burn will always be the one that draws from — and gives back to — its own landscape.
Because all energy has consequences; the difference lies in whether those consequences are visible, local, and regenerative — or hidden, distant, and destructive.

Every power station, panel or pipeline leaves a scar somewhere. The only honest energy is the one we can see, understand, and take responsibility for.

MOISTURE: THE HIDDEN ENEMY
Freshly cut wood can hold 50%–90% moisture depending on the tree species and time of year it was harvested.
Wet logs give little usable heat because most of the energy is spent boiling off the water before the wood gases can ignite.

Around 80% of wood fuel, depending on species, is volatile gas and 20% is solid charcoal.
When the log is heated in a stove, the wood changes state from a solid to a gas — visible as smoke — while oxygen introduced mainly above the log ignites those gases into flame.

If the timber is wet, those gases mix with steam and fail to reach the temperature required for proper combustion — instead of bright yellow flames, you get smouldering smoke, blackened glass, and tar deposits inside your chimney as the fumes transform into condensate.

This isn’t just wasted energy — it’s wasted potential. It means pollution, poor performance, and premature wear on your stove and flue system. Any smoke that reaches the chimney outlet is lost energy — gases that should be burning off inside the firebox.

Just as any combustion engine or boiler would struggle if its fuel were mixed with water, your stove too performs best when its fuel is properly prepared for combustion.

HOW WOOD DRIES
If wood is stored without adequate ventilation, sunlight or shelter, drying can take one to four years — depending on the species, weather, and stacking method.

Scientific studies confirm that some species such as ash, birch and pine dry faster than other denser or resinous timbers like oak, chestnut or larch that hold moisture for longer.
Air flow and shelter are everything, and like solar panels, sunlight orientation is essential.

At Scarlett Fireplaces, we pass on the experience gathered over decades — advising customers on log supply, preparation and storage that can reduce natural drying time to a single summer season, whatever the species.

A good log store isn’t just a shed — it’s a miniature solar and wind system, open enough to breathe, covered enough to protect, and designed to turn sunlight and air movement into dry fuel efficiency.

The time of year that the fuel is delivered and stacked is crucial in a damp climate.
Always source your wood, whether sold dry or wet, in spring.
Leaving it until October or later adds another level of risk; even dry wood will act like a sponge, drawing in rain and damp.

In the UK, outdoor air humidity often sits above 20% — sometimes double that through autumn and winter.
That’s why internal log storage — keeping a few days’ worth of fuel inside — is so important.
It releases the last remnants of excess water, which in turn helps to humidify the room, balancing the air where a stove might otherwise over-dry it.

WHAT IS 'DRY' WOOD?
There’s often confusion about what “dry logs” really means.

Some wood is kiln-dried — placed in an oven to remove moisture quickly, often using electricity or fossil fuels for the process.
The end product is then bagged in plastic and shipped.
A common concern with this process is that, when dried too fast, the outer shell of the log can harden and seal, trapping moisture inside and reducing true dryness.

Then there’s seasoned wood — timber that has been cut, split, and left to dry naturally.
The time needed to reach optimal dryness depends on the species, the climate, and how the logs are stored.

While some sources, including official data, claim differences between kiln-dried and seasoned wood in how they burn, the basic science is simple: dry wood is dry wood.
Once the moisture content is between 15% and 20%, it makes no difference how that dryness was achieved — the combustion process is identical.

HOW TO LIGHT AN EFFICIENT FIRE FROM THE TOP DOWN
In the UK, we’ve traditionally lit fires from beneath.
Until recently, the first question when showing a customer how to light a stove was: “Have you got any newspaper?”

The typical approach — paper at the base, kindling above, logs on top — looks logical, the traditional scouts’ protocol, but it has two fundamental flaws.

First, lighting from underneath warms all the fuel above, causing it to release smoke before the upper gases are hot enough to ignite.
That unburned smoke goes up the chimney as pollution and wasted energy.

Second, there’s the physics of the chimney draft.
Hot air rises because it’s lighter than cold air — but in midwinter, especially on still, low-pressure days, the air at the top of your flue can be just a few degrees above freezing.
That dense, cold air creates a “cold plug” in the chimney, resisting the initial upward flow of smoke.
When a fire is lit from below, the first smoke produced lacks the heat needed to clear that cold plug, sometimes resulting in smoke spillage into the room.

Lighting from the top down solves both problems.

Open the stove door and place two small logs on the base of the stove, then stack softwood kindling like Jenga on top of them.
Since most homes no longer keep newspapers, add a natural firelighter on top of the kindling.

When you light it, the firelighter produces instant heat without smoke, warming the flue and clearing any cold plug almost immediately.
The kindling below releases gases that pass through the flame above and ignite — creating far less smoke and a far more efficient start.

As the kindling starts to catch, open the air control fully, leaving the door slightly cracked open to allow a fast flow of air directed at the establishing fire.

A fire lit from the top burns downward in stages, with each layer preheated and ready to ignite cleanly.
Once the kindling is engulfed in flame, shut the door — keeping the air control fully open.
When the logs have thoroughly caught, adjust the air control to suit, bearing in mind that modern stoves gain better efficiency as they heat up, because the combustion air introduced over the top of the fire is preheated through air channels surrounding the firebox.

The result: faster chimney warm-up, reduced risk of smoke inside and out, and a more graceful, controllable flame picture.

THE PERFECT BURN
The perfect setting for your stove’s air control isn’t governed by a fixed number, but by the natural engine of your setup — the chimney draft — combined with the visual cue of slow, bright, licking flames.
The height of the chimney, the number of bends, and even the weather conditions all influence the strength of the draw and how quickly air is pulled through the control.

Finding that perfect balance can be one of the most satisfying parts of owning a wood burner.
But when adjusted incorrectly, it can also promote inefficiency — whether by adding too much air for a roaring fire (sending useful heat straight up the flue) or starving the flames of oxygen by closing the control too far and emitting unburned smoke.

Charnwood Stoves’ latest innovation removes that worry.
Their intelligent range features groundbreaking technology that monitors the flame and automatically adjusts the air supply, eliminating human error to deliver the perfect burn every time.

ASH: THE HIDDEN HELPER
Efficient wood burning produces remarkably low ash — typically just 1–2% of the fuel’s original volume.
That small residue is not waste but an ally. A bed of ash helps to insulate the embers, holding heat for longer and allowing a more even burn through the next log.

However, as stoves have evolved to include larger viewing windows for a better flame picture, the space available to retain ash has reduced.
With much of the internal base now viewing glass, there’s less room for ash storage, meaning you may need to empty the ash more often to maintain airflow and prevent obstruction.

A thin layer of ash is ideal — too much restricts air beneath the firebed; too little loses valuable heat.
As with all aspects of good burning, balance is everything.

THE RHYTHM OF FIRE
There are two stages in wood combustion. The first is gasification, when the smoke ignites into flame and warmth. The second is the charcoal burn, which surprisingly doesn’t start until the gases and flames have faded.

The pyromaniacs among us will throw another log on as soon as the flame starts to die — but hold off a few minutes. Let the heat of the char continue to warm the room.

Add the next log just before the embers begin to fade, and the combustion process will begin again naturally: Log gets hot, releases its gases, oxygen from above ignites it.

Holding off on that next log might save you one or two over an evening. An evening over a week, a month, or a whole burning season soon adds up to a few barrow loads.

Remember, every piece of wood is a precious piece of energy, gifted by nature, and your modern stove allows you the understanding of the science behind it all, literally before your eyes. 

BEYOND FUEL — A LOCAL PHILOSOPHY
Wood burning, when practised with understanding, is not just a source of heat.
It’s a living example of circular energy, where responsibility, comfort and ecology align.
A well-seasoned log is not waste, it’s stored sunlight, captured through photosynthesis, harvested with care, and returned as warmth; the original eco battery.

By burning wood correctly, we not only heat our homes, we feed a local cycle of woodland care; rewarding, satisfying work that brings pride, purpose and wellbeing to those who carry it out, and to those who walk the green spaces they create.
Compared to the grind of bolting together solar farms or maintaining distant industrial sites, working with the woodland is a reconnection, energy with meaning, labour with legacy.

That is what a sustainable energy future truly means.