Desk research, not testing. Look Into has not burned these fuels or used these fire pits. Every figure below is arithmetic on a retail price we read on 16 October 2026, plus a stated burn rate. Change the burn rate and the answer changes, so we show both.
Prices and specs last checked by Look Into on 16 October 2026 · next check 4 January 2027 · how we picked
The short version
- A 2.5 hour evening on kiln-dried hardwood costs about £5.00 at 16 October 2026 prices (2kg an hour at £1.00 a kg).
- Patio gas costs about £7.83 for the same evening at a 10kW flame, and £11.35 with the burner on full. That is 57% more than wood at the base setting.
- Lumpwood charcoal comes in at about £4.10, but it gives a glow rather than flames and needs firelighters.
- Bioethanol looks cheapest at £2.50, but only because a tabletop burner gives out roughly a fifth of the heat of a wood fire. Per unit of heat it is the dearest fuel here, at 56.8p per kWh against 24.4p for wood.
- One line for most households: if you want warmth, kiln-dried Ready to Burn hardwood is the cheapest real heat at about £2 an hour. Pay the gas premium only for the convenience or the lack of smoke.
Look Into's October 2026 Fire Pit Fuel Cost Index
Ranked by cost of a 2.5 hour evening. Prices checked 16 October 2026.
| Rank | Fuel | Price used | Burn rate (assumed) | Per hour | 2 hour evening | 2.5 hour evening | Low to high (2.5h) |
|---|---|---|---|---|---|---|---|
| 1 | Bioethanol | £3.33/L | 0.3L/h | £1.00 | £2.00 | £2.50 | £1.51 to £4.75 |
| 2 | Lumpwood charcoal | £1.64/kg | 1.0kg/h | £1.64 | £3.28 | £4.10 | £2.81 to £9.19 |
| 3 | Kiln-dried hardwood | £1.00/kg | 2.0kg/h | £2.00 | £4.00 | £5.00 | £3.05 to £8.31 |
| 4 | Propane (13kg patio gas) | £4.04/kg | 0.775kg/h (10kW) | £3.13 | £6.26 | £7.83 | £3.91 to £11.35 |
Cost per unit of heat, the fairer ranking
A cheap evening is not the same as cheap warmth. This table divides each fuel's price by the energy it holds.
| Rank | Fuel | Energy content | Price | Cost per kWh of fuel | Heat at the base burn rate |
|---|---|---|---|---|---|
| 1 | Kiln-dried hardwood (20% moisture) | 4.1 kWh per kg | £1.00/kg | 24.4p | 8.2kW |
| 2 | Propane | 12.9 kWh per kg | £4.04/kg | 31.3p | 10kW |
| 3 | Bioethanol | 5.87 kWh per litre | £3.33/L | 56.8p | 1.8kW |
| n/a | Lumpwood charcoal | not sourced | £1.64/kg | not calculated | not calculated |
We left charcoal out of the heat ranking because we could not find a UK public-body figure for its energy content. We would rather leave the cell empty than fill it with a number we cannot point to.
The matched-heat evening
To compare like with like, Look Into prices every fuel at the same heat: the 20.5 kWh a 2.5 hour wood fire gives at 2kg an hour (5kg × 4.1 kWh).
| Fuel | Fuel needed for 20.5 kWh | Cost |
|---|---|---|
| Kiln-dried hardwood | 5.0kg | £5.00 |
| Propane | 1.59kg | £6.42 |
| Bioethanol | 3.49 litres | £11.64 |
At matched heat, gas costs 28% more than wood and bioethanol costs 133% more. No tabletop bioethanol burner we know of can put out 8.2kW, so treat that last line as a price comparison, not something you could actually do.
The working, line by line
Kiln-dried hardwood
- £19.99 ÷ 20kg = £0.9995 a kg, rounded to £1.00 - 2.0kg an hour × £1.00 = £2.00 an hour - 2.5 hours × £2.00 = £5.00 - Low: 1.5kg/h × 2.5h × £0.8135/kg (£17.49 ÷ 21.5kg) = £3.05 - High: 3.0kg/h × 2.5h × £1.1083/kg (£19.95 ÷ 18kg) = £8.31 - Energy: 4.1 kWh per kg at 20% moisture (Forest Research). £1.00 ÷ 4.1 = 24.4p per kWh. 2kg/h × 4.1 = 8.2kW
Lumpwood charcoal
- £19.70 ÷ 12kg = £1.642 a kg - 1.0kg an hour × £1.642 = £1.64 an hour - 2.5 hours × £1.642 = £4.10 - Low: 0.75kg/h × 2.5h × £1.499/kg (£14.99 ÷ 10kg) = £2.81 - High: 1.5kg/h × 2.5h × £2.45/kg (£24.50 ÷ 10kg) = £9.19 - Firelighters are extra. Our firelighter cost study found 3.7p to 12.5p a lighter on 12 October 2026.
Propane
- £52.50 ÷ 13kg = £4.0385 a kg - 10kW ÷ 12.9 kWh/kg = 0.7752kg an hour - 0.7752 × £4.0385 = £3.13 an hour - 2.5 hours × £3.1306 = £7.83 - Full 14.5kW: 14.5 ÷ 12.9 = 1.124kg/h × £4.0385 = £4.54 an hour, £11.35 for 2.5 hours - Low 5kW: 5 ÷ 12.9 = 0.3876kg/h × £4.0385 = £1.565 an hour, £3.91 for 2.5 hours - A 13kg bottle lasts 13 ÷ 0.7752 = 16.8 hours at 10kW, which is 6.7 evenings of 2.5 hours. At full 14.5kW it lasts 11.6 hours - Energy: £4.0385 ÷ 12.9 = 31.3p per kWh - The smaller 5kg bottle costs £23.25 ÷ 5 = £4.65 a kg, 15% more per kg than the 13kg
Bioethanol
- £19.99 ÷ 6L = £3.3317 a litre - 0.3L an hour × £3.3317 = £1.00 an hour - 2.5 hours × £1.00 = £2.50 - Low: 0.2L/h × 2.5h × £3.01/L (£36.12 ÷ 12L) = £1.51 - High: 0.5L/h × 2.5h × £3.80/L (£19.00 ÷ 5L) = £4.75 - Energy: 26.8 MJ/kg × 0.789 kg/L = 21.1 MJ/L = 5.87 kWh/L. £3.3317 ÷ 5.87 = 56.8p per kWh. 0.3L/h × 5.87 = 1.76kW - Some bioethanol sold for fires is below pure strength (one listing we saw was sold as 80%). Weaker fuel holds less energy, so the real cost per kWh will be higher than 56.8p.
What moves the numbers
- Flame size. This matters most for gas. The same fire pit costs £3.91 or £11.35 for an evening depending on where the knob sits.
- Wood moisture. The 4.1 kWh per kg figure is for wood at 20% moisture. Wetter wood spends part of its energy boiling off water, so you burn more for the same heat and get more smoke.
- Gas burner rating (kW, sometimes shown as BTU). A listing's kW figure is the maximum the burner can draw, not what it uses on a normal evening. 1kW is about 3,412 BTU per hour.
- Bottle size. 5kg patio gas costs 15% more per kg than 13kg.
- Wind. Open flames lose heat sideways in wind. Glass wind guards on gas pits help the flame stay lit but do not change the fuel arithmetic.
- Fire pit design. A double-wall "smokeless" pit burns hotter and cleaner. No maker in our shortlist publishes a burn rate, so we have used the same 2kg an hour for every wood pit. That may flatter the hotter-burning designs.
UK rules that touch fire pits
Smoke Control Areas. The gov.uk rules say that in a Smoke Control Area "you cannot release smoke from a chimney", with a penalty in England of up to £300. Those rules are written around chimneys and appliances on buildings. The same gov.uk page says "You're allowed garden bonfires in smoke control areas" and lists outdoor barbecues, chimineas and pizza ovens as usable. It does not mention fire pits by name. Our reading is that a freestanding garden fire pit is treated like a bonfire, not a stove, but check with your council if you live in one.
Ready to Burn. In England, wood fuel sold in volumes under 2 cubic metres must be certified Ready to Burn, which guarantees moisture of 20% or less (gov.uk, Selling wood for domestic use in England). This rule is about selling, not burning. It is still the simplest way for a buyer to know a bag is dry enough. The Alderline logs used in this index carry the certification in their listing. Several cheaper bags we saw said "kiln dried" without saying Ready to Burn.
Smoke nuisance. Even where a fire is allowed, your council can act on smoke that keeps getting into a neighbour's home or garden under the statutory nuisance rules in the Environmental Protection Act 1990. Dry wood, a smaller fire and checking which way the wind is blowing are the practical defences.
FAQ
What is the cheapest fire pit fuel in the UK?
Bioethanol is cheapest per evening at about £2.50 for 2.5 hours, but kiln-dried hardwood is cheapest per unit of heat at 24.4p per kWh (prices checked 16 October 2026). If you want to feel warm, wood wins.
How much does it cost to run a gas fire pit for an evening?
About £7.83 for 2.5 hours at a 10kW flame using a £52.50 Calor 13kg patio gas refill, or £11.35 with a 14.5kW burner on full. That works out at £3.13 to £4.54 an hour.
How long does a 13kg patio gas bottle last in a fire pit?
About 16.8 hours at 10kW and 11.6 hours at 14.5kW, using 12.9 kWh of energy per kg of LPG. That is six to seven 2.5 hour evenings at the lower setting.
How much wood does a fire pit use in an evening?
Look Into assumes about 5kg for a 2.5 hour evening (2kg an hour), within a range of 3.75kg to 7.5kg. A 20kg bag therefore covers about four evenings.
Is it cheaper to burn charcoal or wood in a fire pit?
Charcoal costs a little less per evening on our assumptions (£4.10 against £5.00), but it gives a low glow rather than flames and needs firelighters. Most people use a fire pit for the flames, so wood suits more households.
Can I use a fire pit in a Smoke Control Area?
Probably yes. The gov.uk Smoke Control Area rules cover smoke from building chimneys and say garden bonfires are allowed. Fire pits are not named, so ask your council if you want certainty.
Do I have to buy Ready to Burn wood for a fire pit?
In England, sellers must certify wood sold in bags under 2 cubic metres as Ready to Burn. You are not breaking the law by burning other wood in a garden pit, but wood over 20% moisture smokes more and heats less.
Method, and how to check any of this
- Prices. Read on 16 October 2026 from Amazon UK product pages and search results, shop.calor.co.uk, logsdirect.co.uk and bioethanol-fireplace.co.uk. We took the first unsponsored results with a stated weight or volume.
- Energy content. Wood (4.1 kWh/kg at 20% moisture) and LPG (12.9 kWh/kg) are net calorific values from Forest Research's "Typical calorific values of fuels" table. Bioethanol uses standard reference values for pure ethanol.
- Burn rates. Assumptions, shown with a low and high case. Look Into has not measured any of them.
- To check our numbers yourself: take today's price of the bag or bottle, divide by its weight or volume, multiply by the burn rate, then by the hours. For gas, divide the burner's kW by 12.9 to get kg per hour.
Update cadence. Re-check the four fuel prices quarterly, on the first working day after each Ofgem cap change (next: early January 2027), and add a dated line rather than overwriting old figures. Re-check Calor patio gas in March 2027 before the spring season.
How to cite this page: "Look Into's October 2026 Fire Pit Fuel Cost Index (lookinto.co.uk, prices checked 16 October 2026) puts a 2.5 hour fire pit evening at £5.00 on kiln-dried hardwood and £7.83 on patio gas."
The practical recommendation
For most UK households, a wood-burning fire pit fed with Ready to Burn kiln-dried hardwood is the cheapest way to sit outside and actually feel warm, at about £2 an hour. Buy logs by weight, not litres, so you can compare price per kg. If smoke and your neighbours are the bigger worry, gas costs about £2.83 more per evening at a 10kW flame, which is the price of no smoke and no ash.
Sources: Calor patio gas bottles · Alderline logs, Amazon UK · Logs Direct lumpwood charcoal · EKOFUEL 6L, Amazon UK · bioethanol-fireplace.co.uk 5L · Forest Research calorific values · gov.uk Smoke Control Area rules · gov.uk Selling wood for domestic use in England
Affiliate disclosure: links to Amazon are affiliate links. As an Amazon Associate, Look Into earns from qualifying purchases. This does not change our numbers or our ranking.