Wood heat is cheap only if you burn it right

Only under one condition, and the accounts are blunt about it: the wood has to be cheap or free. Where people save real money — one account puts it at well over a thousand a year against heating oil — they are cutting fallen wood on their own land, or taking dead trees off public land on an inexpensive permit, and doing the labour themselves. The moment you have to buy the wood cut, split and delivered, most of the saving is gone, and what is left has to cover the equipment: a saw and a splitter cost money and wear out, and a stove and its chimney are a real up-front bill. On top of the money is the time. Wood heat is a lot of ongoing physical work — cutting, splitting, stacking, carrying, cleaning ash — and the accounts split on whether that is a cost or a pleasure: some love it and would do it anyway, others find it takes over their winter. It is heavy, repetitive work, and done with poor technique it can strain a back or a shoulder, so it is fair to count your time and your body in the price, not just the fuel. One more money note: tell your insurer, and have the stove installed and inspected properly, because some carriers raise the premium and, worse, an uninspected installation can get a fire claim refused.

Anything that is not plain, raw, untreated wood. Three separate conversations, and a stack of the accounts' own cautions, say never to burn wood that has been treated, painted, or glued: pressure-treated lumber and old decking, painted or stained boards, plywood, chipboard and other engineered board, and railway sleepers, which are soaked in creosote. Burned, these give off genuinely toxic fumes — arsenic in the oldest treated wood, copper compounds and other poisons in newer kinds, coal-tar chemicals from sleepers — and in many places burning them is also illegal. The trap one account points out is that treated wood is hard to spot once it has weathered: the green tint fades to grey and the smell disappears, so you cannot always tell by looking or sniffing. The safe rule is the simple one: if you did not see the tree it came from, or it is coloured, painted, stamped, or was used outdoors to resist rot, do not put it in the fire. Also off the list are a few natural woods and plants the accounts name — poison ivy, oak and sumac, and some ornamental shrubs — whose smoke is an irritant or worse. Wood you cannot safely burn is not rubbish for the stove; it goes to proper disposal, which may cost a little.

Because wet wood and a dirty chimney are the pair that cause chimney fires, and a chimney fire can burn your house down. Freshly cut wood is heavy with water, and the accounts say it needs to dry — season — for six months to a year before it will burn well. Burn it wet and three bad things happen at once: much of the fire's heat is wasted boiling the water out instead of warming the room, so you get less heat for more wood; it smokes heavily; and that smoke leaves a tarry deposit called creosote on the inside of the chimney. Creosote is flammable, and when enough of it builds up it can catch and roar — one account describes having several chimney fires, one needing the fire brigade. The two habits that prevent it are to burn only seasoned wood and to have the chimney swept once a year. A related sign to watch: a modern stove burning dry wood well shows almost no smoke from the chimney, so a steady plume of smoke usually means the wood is wet or the fire is being starved of air, wasting fuel and coating the flue. Keep the fire hot and the wood dry, and sweep every year.

A stove, not an open fireplace, and the wood well away from the house. The accounts are firm that an open fireplace is close to useless for heating: it sends most of its heat straight up the chimney and pulls cold air into the rest of the house to replace it, so a room can actually end up colder. A closed wood stove, or an insert fitted into an existing fireplace, holds the heat and radiates it, and can warm a good part of a home; it is the difference between wood as decoration and wood as heating. On storage, the rule the accounts repeat is to keep the woodpile away from the walls of the house, raised off the ground, and covered. Wood stacked against the house is an invitation to termites, ants, spiders, rats and other pests, which move from the pile straight into the structure — and a brick or concrete or clad wall does not stop them, because they travel through small gaps and up behind the facing. In a wildfire-prone area there is a second reason: a stack of dry fuel against the house makes it far harder to defend, and the accounts note that firefighters may have to leave such a property. A few feet away, off the ground, under a cover, is the pattern.