Fuel is where a household running on fire either saves money and stays well, or slowly poisons itself and wrecks a chimney. The list of things that must not go in a stove is short, specific and widely ignored, usually because the offending material was free.
The other half of the page is simpler than most people expect: how dry the wood is matters far more than what species it is.
The never list
Also avoid, for the stove's sake rather than yours: wood with nails and screws in it, which damage the grate and the liner, and very resinous softwood burned exclusively, which tars a flue faster.
Dryness beats species
A dry softwood log is better fuel than a wet hardwood one, and this surprises people who have been told to burn only hardwood.
Water in wood absorbs a large amount of heat simply to evaporate, so a wet log delivers much less heat to the room, burns cooler, and sends unburnt volatiles up a cold flue where they condense as tar. That tar is the fuel for a chimney fire.
A moisture meter costs very little and settles every argument about whether a delivery is genuinely seasoned.
Season it properly: split, stacked off the ground, covered on top and open at the sides, in a windy sunny spot, for one to two years. See split, stack and season firewood.
Which woods, if you have the choice
Once everything is dry, the differences are real and secondary.
Density is what varies. A cubic metre of oak holds far more energy than a cubic metre of pine, and a kilogram of each holds roughly the same. So hardwood is better value by volume, and softwood is perfectly good fuel if you have it.
A mix is ideal: softwood to get it going hot and fast, hardwood to hold it.
Bought fuel and the law
Restrictions apply, and they vary by nation.
- Wet wood sold in small volumes and traditional house coal are restricted in England under air quality regulations, and similar measures apply elsewhere in the UK.
- Look for the Ready to Burn mark on bagged wood and manufactured fuel, which certifies the moisture content.
- Smoke Control Areas cover much of urban Britain. In one, you may only burn authorised fuels, or burn any fuel in an exempt appliance. Most modern stoves are exempt appliances; an open fire generally is not.
- Check whether you are in a Smoke Control Area with your local council. Many people are and do not know.
Buying loose seasoned wood in bulk remains lawful and is much cheaper, and it is where the moisture meter earns its place.
Coal, briquettes and the rest
- Burn only what the appliance is rated for. A wood-only stove has no grate and no ashpan air, and burning coal in it damages the stove and can be dangerous. Multi-fuel stoves have a riddling grate and can take both.
- Smokeless fuels are the authorised option in Smoke Control Areas and burn hotter and longer than wood.
- Manufactured heat logs and briquettes are compressed sawdust, are very dry, and burn hot. Follow the maker's guidance on how many, because they expand and can overfire a small stove.
- Wood pellets need a pellet appliance.
- Peat burns cool and smoky and its extraction is environmentally serious.
- Never mix wood and coal in the same load unless the appliance manufacturer says you may, and never burn coal on an open wood fire.
Home-made paper briquettes are covered separately. See make fuel briquettes from waste paper.
Pallets and salvaged timber
The commonest source of free fuel and the one that needs the most care.
Pallets can be fine, and they can be treated. Look at the stamp:
- HT means heat treated, which is a physical process and the timber is safe to burn.
- MB means methyl bromide fumigated. Do not burn it.
- No stamp means unknown. Treat as unknown.
- Painted, stained or chemically stained pallets, or ones that have carried chemicals, should not be burned regardless of the stamp.
Denail everything before it goes near a stove or a saw.
Construction offcuts are the biggest trap. Skirting, architrave and studwork are usually plain softwood and fine; anything painted, glued, laminated or engineered is not. Sort it at the skip, not at the fire.
Old furniture is usually varnished, glued or chipboard. Almost none of it is stove fuel.
Free wood, safely
Where the good free fuel actually is.
- Storm-felled branches and windblow, with the landowner's permission.
- Tree surgeons, who pay to dispose of arisings and will often drop a load. Ask, and be ready to take it green and season it yourself.
- Hedge cutting and coppicing, with permission. Hazel, ash and hawthorn all coppice and regrow.
- Council and estate work.
- Neighbours felling something. See community and mutual aid.
- Untreated builders' offcuts, sorted carefully.
Always ask. Taking wood from land without the owner's consent is theft, and the same reasoning applies as on the rules and the law of foraging. Permission is usually given and it makes everything simpler.
Take it green and season it. Free wood is almost always wet wood, and the two year lead time is the real cost. Which is the argument for starting the stack now rather than in the autumn you need it.