Best Fuel & Heat Value Calculator

Fuels ranked by heat

11 fuels

Heat is what one item releases when burned. Heat per copper divides it by the item's portal price (when it can be bought) or its base value. One Plank is 20 heat.

Fuels by heat value, heat per copper and plank equivalents
Fuel	Heat	Heat / copper	= Planks	On a Crucible	Sells for
Panacea PotionMade in Advanced Blender	320,000	10.7	16,000	80,000 s	30s
Blast PotionMade in Advanced Blender	24,000	9.39	1,200	6,000 s	2s 557c
Black PowderMade in Advanced Blender	6,000	9.09	300	1,500 s	660c
Coke PowderMade in Grinder	660	22	33	165 s	—
CokeMade in Athanor	600	20	30	150 s	—
CoalMade in Stone Crusher	540	13.5	27	135 s	—
Coal OreBulk: 120 portions · bought at the portal	250 /portion	6.25	12.5	62.5 s	—
Charcoal PowderMade in Grinder	48	24	2.4	12 s	—
CharcoalMade in Crucible	40	20	2	10 s	—
PlankMade in Table Saw	20	20	1	5 s	—
LogsBulk: 200 portions · bought at the portal	10 /portion	10	0.5	2.5 s	—

Bulk fuels (Logs, Coal Ore) are split into portions in the game files; we read their heat value as per portion, the same way recipes count them assumed. “Sells for” is shown only for fuels you can sell in the shop. Steam (20 heat per unit) is not burned: a Steam Boiler makes it from heat and a Steam Heating Pad uses it, see Steam Boiler settings.

Heating calculator

Add the heated machines on your furnaces. We total their heat per second and show how much of each fuel that burns per minute at base speed. The Fuel Efficiency upgrade adds 10% heat per level in the upgrade data; we assume it multiplies each fuel's heat.

Machine
Count
Machine 2
Count 2

Fuel Efficiency upgrade assumed

Heat needed88heat / s

5,280 heat / min · 316,800 heat / h

Fuel needed per minute for the selected machines
Fuel	Heat each	Per minute	Per hour	One lasts
Panacea Potion320,000 heat · lasts 60.6 min	320,000	0.02/min0.99/h	0.99	60.6 min
Blast Potion24,000 heat · lasts 4.55 min	24,000	0.22/min13.2/h	13.2	4.55 min
Black Powder6,000 heat · lasts 68.2 s	6,000	0.88/min52.8/h	52.8	68.2 s
Coke Powder660 heat · lasts 7.5 s	660	8/min480/h	480	7.5 s
Coke600 heat · lasts 6.82 s	600	8.8/min528/h	528	6.82 s
Coal540 heat · lasts 6.14 s	540	9.78/min586.7/h	586.7	6.14 s
Coal Ore120 portions each · 30,000 heat · lasts 5.68 min	30,000	0.18/min10.6/h	10.6	5.68 min
Charcoal Powder48 heat · lasts 0.55 s	48	110/min6,600/h	6,600	0.55 s
Charcoal40 heat · lasts 0.45 s	40	132/min7,920/h	7,920	0.45 s
Plank20 heat · lasts 0.23 s	20	264/min15,840/h	15,840	0.23 s
Logs200 portions each · 2,000 heat · lasts 22.7 s	2,000	2.64/min158.4/h	158.4	22.7 s

Machine heat use

Heat per second while the machine runs, at base speed. A faster machine draws proportionally more per second; heat per craft stays the same.

Heat drawn per second by each heated machine
Machine	Heat / s	Heat / min	Coke / min	Source
Crucible	4	240	0.4	Game data
Stackable Crucible	6	360	0.6	Game data
Thermal Extractor	80	4,800	8	Game data
Paradox Crucible	1,200	72,000	120	Game data
Kiln	15	900	1.5	Game data
Alembic	108	6,480	10.8	Game data
Athanor	32	1,920	3.2	Game data
Advanced Alembic	270	16,200	27	Game data
Advanced Athanor	360	21,600	36	Game data
Iron Smelter	9	540	0.9	Game data
Advanced Athanor (Athanor recipes)	32	1,920	3.2	Cited source
Steam Boiler (Low setting)	100	6,000	10	Cited source
Steam Boiler (Mid setting)	500	30,000	50	Cited source
Steam Boiler (High setting)	3,000	180,000	300	Cited source
Cauldron (depends on product)	0.33–166.7	20–10,000	—	Cauldron curve

Advanced Athanor on Athanor recipes: Community calculator engine (starfi5h, DB v50+): the Advanced Athanor also runs the Athanor recipes that carry a CatalystCost, drawing 32 heat/s for them. Not traced in the game binary (see PheeZz research/07-catalysts-cauldron.md). citation

Cauldron: Cauldron craft time and heat are a piecewise-linear interpolation over the output item's CauldronTarget (community calculator engine). The time curve reproduces the CraftingTime of all four Cauldron rows in DT_EnemyCrafting (checked by pipeline tests), heat is per batch. citation

Heat sources: Stone Furnace, Blast Furnace, Steam Heating Pad. Their heating area (how many machines fit above them) is computed in-game and not in the data.

Steam Boiler settings

The Steam Boiler turns heat into Steam at one of three settings. The settings are not in the data tables; they come from the game binary (cited below).

Steam Boiler output and heat per setting
Setting	Steam / cycle	Cycle	Steam / min	Heat / s	Heat per Steam
Low	30	6 s	300	100	20
Mid	100	4 s	1,500	500	20
High	300	2 s	9,000	3,000	20

Source: PheeZz research 06: SteamBoilerComponent settings read from the game binary (OutputSteamCount / BoilingTotalTime, 20 heat per Steam at every setting); High matches starfi5h's 'Steam Boiler (High)'. citation

Steam Heating Pad: how much Steam it uses per unit of heat on 1.0 is unverified, so we do not convert Steam back into heat. It is computed in-game.

Heat rules in 1.0

The 1.0 patch notes say: “Removed the base heat cost of all heating devices.” A furnace only burns fuel for the machines it heats, so fuel use = the machines' heat per second ÷ the fuel's heat.
Machine heat per second is the machine's heat cost × its speed. Heat per craft does not change with speed, so upgrades that speed machines up raise heat per second.
Thermal Extractors and Stackable Crucibles draw heat like any other machine (their values are in the table). The Cauldron's heat depends on what it makes.
Not modelled: research multipliers other than the optional Fuel Efficiency setting, and anything the game computes at runtime.

Fuel FAQ

What is the best fuel in Alchemy Factory?

By heat per item, Panacea Potion is the strongest fuel (320,000 heat each). By heat per copper of its base value, Charcoal Powder is the most efficient (24 heat per copper). Selling a fuel instead of burning it can be worth more: check the “Sells for” column.

Coal vs coke: which is better?

Coke gives 600 heat against Coal's 540, and ground Coke Powder gives 660. Turning Coal into Coke in a Crucible takes 6 s, which costs 24 heat at the Crucible's 4 heat/s, so each conversion nets about 36 extra heat. Per copper of base value Coke is 20 heat against Coal's 13.5.

Should I burn Coal Ore or crush it into Coal first?

Burning Coal Ore directly gives 250 heat per portion (30,000 per ore, if heat applies per portion as recipes count it). Crushing one ore in a Stone Crusher gives 120 Coal worth 64,800 heat, so crushing first more than doubles the heat.

How many crucibles can one furnace heat?

The data gives each machine's heat use per second (a Crucible draws 4 heat/s), so fuel use is easy to total with the calculator. How many machines fit on a furnace's heating area is not in the game data we extract, so check it in-game. Since 1.0 the furnace itself has no base heat cost.