Wood Burner vs Gas Central Heating Cost Calculator
Almost every comparison online is written by someone selling stoves or boilers. This one isn't — we sell neither. Enter your real log price, stove efficiency, and gas unit rate to see what a kilowatt-hour of heat actually costs from each, in pence, plus the honest one-room-vs-whole-house catch that decides whether a wood burner saves you money. Everything runs in your browser; nothing is uploaded.
Your logs and stove
Kiln-dried hardwood typically runs about £100–£150 per loose cubic metre delivered (a builder's bulk bag holds ~0.7–0.9 m³ — divide what you pay by what you get). Loose-fill hardwood weighs roughly 250–320 kg per m³. Seasoned wood at 20% moisture holds about 4.1 kWh per kg — the calculator derives this from your moisture figure. Efficiency presets are typical; your stove's manual or its listing has the real number.
Your gas central heating
6.3p per kWh is a mid-2026 GB price-cap-era estimate — the cap changes every three months, so copy the exact unit rate from your bill or tariff. Boiler presets are typical in-use figures; your boiler's ErP label or service report has the real one.
How you'd run the stove
Nominal output is on the stove's data plate — typical living-room stoves are 4–5 kW. The scenario buttons are common patterns; edit any number. Upkeep covers kindling, firelighters, and the annual chimney sweep (~£60–£80) — never skip the sweep to save money.
Result
Rules and safety (UK)
Burn dry wood — it's the law of the land and the physics. Wood sold in England in volumes under 2 m³ must be certified "Ready to Burn" at 20% moisture or less. Wetter wood wastes its heat boiling off water, coats your flue with creosote (the fuel of chimney fires), and smokes. If you season your own, check it with a moisture meter before burning.
Check whether you're in a smoke control area. Most UK towns and cities are. There you can be fined for chimney smoke unless you burn authorised fuel or use a DEFRA-exempt appliance — see the official smoke control area rules and check with your council before installing anything.
Sweep the chimney at least once a year when burning wood — more if you burn heavily. The sweep is in this calculator's running costs on purpose: it is not optional, and skipping it trades pounds for a chimney-fire and carbon-monoxide risk. Fit a carbon monoxide alarm in the stove room (required for new installations).
Keep your gas boiler serviced annually either way. A stove doesn't replace the boiler or its safety checks — use a Gas Safe registered engineer. Nothing on this page is a reason to skip servicing.
Assumptions & FAQ
Where does the gas price come from?
The 7.3p/kWh default matches the Ofgem price cap unit rate for Jul–Sep 2026 (recent quarters ranged roughly 5.7–7.3p/kWh), set when this page was last updated in July 2026. The cap resets every three months and tariffs vary — always type the unit rate from your own bill. The comparison deliberately ignores gas standing charges (~30p/day), because a stove doesn't remove them: you keep paying the standing charge unless you disconnect gas entirely.
Where do the log and energy figures come from?
Delivered kiln-dried hardwood in bulk bags typically works out around £100–£150 per loose cubic metre in most of the UK, varying with region and season — get local quotes and edit the price. Loose-fill hardwood logs weigh roughly 250–320 kg per m³. The energy figure is derived from your moisture number: oven-dry wood holds about 5.3 kWh/kg, falling as moisture rises — about 4.1 kWh/kg at the 20% Ready to Burn standard — consistent with Forest Research's typical calorific values. All of it is editable because your logs, not averages, decide your cost.
Where do the efficiency presets come from?
An open fireplace sends most heat up the chimney (~15–25% efficient). Stoves from the 1990s–2000s typically manage ~60–70%. New stoves sold in the UK since 2022 must meet Ecodesign rules, which in practice means ~75–80%+. For boilers: older non-condensing models run ~70–80%, condensing boilers ~85–90% in use, and new A-rated units are rated ~92–94%. These are typical figures — flag them as estimates and use your appliance's real numbers where you know them.
If logs cost more per kWh, how does anyone save money with a stove?
Zoning. A stove heats one room; your boiler heats the whole house. At typical prices a kWh of stove heat costs more than a kWh of gas heat — but an evening in the living room might need 4–5 kW there while the boiler would have burned gas keeping every room warm. If having the stove lets you drop the whole-house thermostat and stop heating rooms you're not in, the gas you avoid can exceed the stove's running cost. That behaviour change — not cheap fuel — is the real mechanism, which is why the result spells out the break-even figure instead of pretending log heat is cheap.
Do you sell stoves, logs, or boilers — or earn from links?
No. This page has no affiliate relationship with any stove maker, fuel merchant, installer, or energy supplier, and no tracking links to any of them. That neutrality is the point of the tool. If that ever changes, it will be disclosed here.
Do my numbers get uploaded?
No. The page is fully client-side; everything is calculated in your browser.