Factorio: Choosing Between Steel and Electric Furnaces

Upgrade stone when space is tight

Steel furnaces offer a clear throughput gain over stone without taking more floor space. The supplied snapshot lists speed 2 for steel and 1 for stone, and both machines occupy a 2×2 footprint. The Factorio Wiki likewise describes steel as twice as fast as stone. That makes steel a practical choice when a smelting block needs more output but cannot expand.

The tradeoff is pollution: the snapshot lists 4 for steel and 2 for stone, and the wiki gives the same relationship per minute. Both furnaces burn chemical fuel, and each has listed usage of 90. Steel keeps a burner line’s fuel requirements while increasing its listed speed, so replace machines when output is a real constraint; a stone furnace that already meets demand need not be upgraded.

References: Factorio versioned crafting sources, Steel furnace - Factorio Wiki

Electric trades fuel delivery for power and space

Electric furnaces match steel’s default speed of 2, but take a 3×3 footprint instead of 2×2. They run on electricity, with listed usage of 180 and drain of 6, and have two module slots. That can suit a factory where fuel delivery is inconvenient or modules are part of the production plan, provided the electrical network can carry the load.

Their machine pollution is listed as 1, below steel’s 4. That figure alone does not establish a factory-wide pollution reduction: the wiki explains that boiler-generated electricity can erase the apparent advantage, while more effective power generation and modules can make electric furnaces more beneficial. Compare your actual power source and layout before converting; there is no universal best furnace independent of those constraints.

References: Factorio versioned crafting sources, Electric furnace - Factorio Wiki

Choose by the line’s bottleneck

If limited floor space or fuel-based operation matters most, steel is a compact way to raise listed speed over stone. If delivering fuel is the problem and power is available, electric removes the need to supply burner fuel to each furnace. If the existing line already keeps up, saving materials for another bottleneck is a sound choice. Electric’s module slots may also matter for a production plan; the snapshot lists electric furnaces among the items used in production science pack, but that connection alone is not a reason to convert every smelting line.

References: Factorio versioned crafting sources, Electric furnace - Factorio Wiki

Shopping list for a four-furnace conversion

For four steel furnaces, gather 24 steel plates and 40 stone bricks. For four electric furnaces, gather 40 steel plates, 20 advanced circuits, and 40 stone bricks. These are exact totals from the supplied recipes multiplied by four; they count only the furnace ingredients, not the materials needed to make those ingredients. Both recipe entries list assembling machine 1, 2, or 3 as the crafting station.

The electric option therefore adds 16 steel plates and 20 advanced circuits to this example, with no change in stone bricks. Check those ingredient costs and the larger footprint against the benefit you expect before queueing a broad replacement.

References: Factorio versioned crafting sources

Make the conversion selective

A useful plan can mix furnace types. Keep steel in compact burner-fed blocks, use electric where fuel logistics or module use makes it worthwhile, and leave stone in place when its output is sufficient. Compare machine speed, space, fuel or power supply, and pollution together; none of those figures alone settles the decision.

References: Factorio versioned crafting sources, Steel furnace - Factorio Wiki, Electric furnace - Factorio Wiki