A wood burning stove sits in an odd spot on the energy map. People fit one for the look and the feel of a real fire, then quietly hope it is also saving them money. Whether it does depends almost entirely on one thing: where your logs come from and what you pay for them. The same stove, in the same room, can be among the cheapest heat in the house or among the dearest, separated only by how you buy the wood. This guide prices a stove honestly, in pence per kWh of heat like everything else on the site, shows why a small forecourt net of logs is the worst way to buy and a bulk load the best, and works through a full winter season so you can see whether a stove pays for the room you actually use it in.
The short answer. Dry wood holds roughly 4 kWh of energy per kilogram at the right moisture level, and a modern stove turns about three quarters of that into useful heat, so call it 3 kWh of warmth per kg of good logs. The cost per kWh then swings wildly with how you buy: small nets from a garage forecourt can work out around 20p per kWh, dearer than gas, while a bulk load of seasoned logs can be 7p or less, and free, well dried wood is close to nothing. The stove itself barely matters next to the price of fuel going into it.
When a stove saves money, and when it does not
A stove earns its keep when it lets you heat the room you are actually sitting in while turning the central heating down, and when the wood is cheap. Spend a winter evening in one warm living room with the rest of the house ticking over cooler, fuelled by logs you bought in bulk or gathered yourself, and a stove is some of the cheapest comfort you can buy. The savings come from heating one space well rather than the whole house, which is the same logic that makes heating one room cheaper in general.
It stops saving money the moment the wood gets expensive or the heat goes to waste. If you buy logs in small bags at convenience prices, you may be paying more per kWh than you would for the gas central heating you are trying to avoid. And if the stove heats a room nobody is using, or the fire roars away while windows are cracked open because it is too hot, the money goes straight up the chimney. A stove is a tool for cheap, focused heat; used as a decorative bonfire it is an expensive hobby.
What a kWh of wood heat actually costs
To compare a stove with anything else, get the wood onto pence per kWh of useful heat. Two numbers do it. Properly dried wood, at around 20 per cent moisture, holds close to 4 kWh per kilogram. A modern stove runs at roughly 75 to 80 per cent efficiency, so each kilogram delivers about 3 kWh of heat into the room. Wet or unseasoned wood ruins this: a log at 40 or 50 per cent moisture wastes much of its energy boiling off water before it can warm you, which is why moisture content matters more than the species of tree.
Now the price, which is where stoves live or die. The same wood costs very different amounts depending on how you buy it:
| How you buy the wood (illustrative) | Example price | Cost per kWh of heat |
|---|---|---|
| Small nets from a forecourt or shop | about 60p per kg | about 20p |
| Bulk kiln-dried logs, by the load | about 35p per kg | about 12p |
| Bulk seasoned hardwood, by the load | about 20p per kg | about 7p |
| Free wood you season yourself | near zero | near zero, plus your time |
Illustrative prices to show the method, not current quotes. Wood prices vary a lot by region, season, species and order size. Assumes about 3 kWh of useful heat per kg of well dried wood.
For context, mains gas heat sits around 8p to 9p per kWh once you allow for boiler losses, and standard electric heating is well over 20p. So bulk seasoned logs undercut gas, bulk kiln-dried is roughly level with it, and small forecourt nets are dearer than gas and not far off electric heating. The lesson is blunt: the cheapest stove and the priciest are the same appliance, and the difference is entirely in the woodpile.
Buying wood: seasoned, kiln-dried and Ready to Burn
Three terms decide what you are really buying. Seasoned wood has been cut and stacked to air dry for a year or two, which brings the moisture down naturally. Kiln-dried wood has been dried mechanically to a low, reliable moisture level, which is why it lights easily and burns clean, and why it costs more. In England, wood sold in small volumes must now carry the Ready to Burn label, which certifies it is dry enough to burn properly; buying anything unlabelled and damp is a false economy because you pay for water that fights your heat.
The single biggest saving is to buy in bulk and store it well. A load delivered by the cubic metre or tonne is far cheaper per kilogram than the same wood in small nets, exactly the way a big bag of anything beats single servings. The catch is that you need dry, airy storage: a log store, a covered side return, anything that keeps rain off while letting air through. Buy cheaper seasoned wood a season ahead, stack it under cover, and you get kiln-dried performance at a fraction of the price. If you have access to free offcuts, fallen timber or pallet wood, seasoning it yourself for a year takes the cost to almost nothing, though never burn painted, treated or manufactured boards, which give off harmful fumes and gum up the flue.
A worked example: a winter of stove heat
Picture a 5 kW stove used as the main heat for a living room on winter evenings. Run flat out it would put out 5 kW, but in normal use you damp it down, so call it an average 3.5 kW of heat over an evening. Four hours an evening is therefore about 14 kWh of heat, which at 3 kWh per kg needs a little under 5 kg of wood a night.
Across a heating season of roughly 150 evenings, that is about 700 kg of wood, near enough three quarters of a tonne. Price it three ways:
- At an illustrative 20p per kg for bulk seasoned logs, around £140 for the winter.
- At 35p per kg for bulk kiln-dried, around £245.
- At 60p per kg for forecourt nets, around £420.
Now weigh that against what it displaces. If the stove lets you keep the gas central heating turned down while you sit in the one warm room, the relevant comparison is the gas you no longer burn heating the whole house, which over a winter can run to a few hundred pounds. Bought sensibly, the stove comes out ahead and pays for its fuel several times over in comfort. Bought as forecourt nets, the sums get marginal, and you may be spending as much on logs as you saved on gas. You can plug your own evenings, hours and wood price into the running-cost calculator to see where your stove lands, and our guide to the cost of heating a house covers the whole-home side of the comparison.
Getting more heat from every log
Once the wood is cheap and dry, a few habits squeeze more warmth from each kilogram:
- Burn dry wood only. This is the whole game. Wet logs waste a third or more of their energy and tar up the flue. A cheap moisture meter pays for itself; aim for 20 per cent or below.
- Run the stove hot, then damp down. Get a brisk fire going so the flue is hot and the burn is clean, then reduce the air to hold a steady output. A starved, smouldering fire wastes fuel and dirties the glass and chimney.
- Do not overfire or overheat the room. Opening windows to dump excess heat is money burned. Match the fire to the room rather than loading it up out of habit.
- Keep the chimney swept. An annual sweep keeps the burn efficient and, more importantly, safe. A blocked or tarry flue is both wasteful and a fire risk.
- Stop the heat escaping the room. A warm living room loses heat through draughts and an open chimney elsewhere; basic draught-proofing and a chimney draught excluder in unused fireplaces keep the warmth where you are paying to make it.
The costs people forget
The logs are only part of the picture. A stove has standing costs that a fair comparison has to include. Installation is the big one: a stove fitted properly, with a lined flue and certified by a competent installer, runs into four figures before you burn a single log, and a brand new chimney or flue system costs more again. That is a one-off, but it means a stove only makes financial sense over years of use, not one cold snap.
Then there are the running extras: an annual chimney sweep, the occasional rope seal or fire brick, a carbon monoxide alarm in the room (which is a legal requirement for a new install and a sensible one for any), and somewhere dry to store wood. None of these is large on its own, but together they mean the true cost per winter is a bit above the bare price of the logs. Air quality is worth a thought too, both indoors and out; burning only dry, certified wood in a clean modern stove keeps emissions down and the flue healthy.
Stove versus the alternatives
As a primary heat source, a stove competes with the boiler and with electric heating. Against gas central heating, a stove burning cheap, dry, bulk wood is competitive or cheaper for heating the one room you live in on winter evenings, which is its natural job. It will not heat the whole house evenly or come on by timer before you wake, so it works best alongside central heating rather than instead of it.
Against plug-in electric heaters it usually wins comfortably on running cost, since even forecourt logs tend to beat electricity per kWh, though the electric heater has no installation cost and no chimney to sweep. And against a heat pump, the comparison is really about different jobs: a heat pump heats the whole home steadily and cheaply once installed, while a stove gives intense, occasional heat in one room with a real flame. Many people end up with both, using the stove for the evenings they want it and the main system for everything else. The wider running-cost picture for each option is laid out in gas versus electric heating costs.
The bottom line
A wood burning stove costs whatever your wood costs, and almost nothing else moves the figure as much. Reckon on about 3 kWh of useful heat per kilogram of well dried logs, then let the buying decide everything: bulk seasoned wood, stored dry, can undercut gas at around 7p per kWh, while small forecourt nets at 20p are dearer than the heating you are trying to replace. Burn only dry, certified wood, run the fire hot then damp it down, keep the flue swept, and use the stove to heat the room you are in rather than the whole house. Do all that and a stove is cheap, pleasant heat; skip it and you have an expensive way to watch a fire. Price your own setup with the running-cost calculator before deciding how much of your heating to hand over to it.