Furnace 19

Lore & Background

In the Factorio universe, smelting is the backbone of every factory. The Stone Furnace, fed by coal or wood, is the first taste of turning raw ore into usable metal. The Steel Furnace, unlocked through the Steel Furnace technology, doubles the smelting speed and represents the player's first real infrastructure investment. The Electric Furnace, the final tier, requires a power grid and offers the highest throughput, anchoring the late-game production lines that stretch across the alien plains. The designation 'Furnace 19' has no foothold in this progression. No technology in the research tree references it, no blueprint string resolves to it, and no in-game NPC or alien artifact alludes to a nineteenth iteration of the smelting unit. What the term *does* evoke, in fan communities, is the feeling of an infinite ladder—a furnace so advanced it belongs to a factory that has already automated itself into the horizon, long after the player has stopped watching. Some modders have used 'Furnace 19' as a placeholder or easter-egg name in custom content, and a handful of speedrun community posts reference it as a fictional 'what-if' tier. None of this constitutes canon, and this encyclopedia records the term strictly as an unverified fan artifact.

In Their Own Story

The cursor hovers over the empty slot in the blueprint grid. The save file was exported from a friend's machine three years ago, and the label reads, in small grey text: *Furnace 19*. She swears she built it. He swears the mod list was clean. They stare at the icon—a furnace, slightly too tall, with a faint blue glow that no vanilla sprite has ever carried—and neither of them deletes it. The factory hums. The alien sky turns the colour of old copper. Somewhere under the conveyor belt, a sound like a bell being struck once, very far away.

Reader's Guide

Because 'Furnace 19' is not a verified item, no research cost, prerequisite chain, or unlock condition can be stated. What *can* be stated is the real furnace progression that any player will actually follow. Stone Furnace is available from the start of the game; no technology is required. It smelts at 0.5 items per second and accepts coal or wood as fuel. Steel Furnace is unlocked by researching the Steel Furnace technology (cost: 30 science packs in basic science; prerequisite: Steel Processing). It smelts at 1.0 items per second and requires coal. It smelts at 1.0 items per second but draws 0.5 MW of power, removing the need for solid fuel entirely. If you encounter 'Furnace 19' in a modpack or a shared blueprint, check the mod's own documentation for its actual unlock conditions, as naming conventions vary widely. In the base game, no such entry will resolve.

Did You Know?

• Factorio's base game contains exactly three furnace types; there is no hidden or secret fourth tier in any released version.
• The Electric Furnace is the only furnace that can be powered by a renewable source like solar panels, making it key to zero-fuel factory designs.
• In the game's internal data files, items are referenced by string identifiers (e.g., 'stone-furnace', 'electric-furnace'); no identifier matching 'furnace-19' appears in the vanilla content.
• The Steel Furnace's 2× smelting speed over the Stone Furnace is one of the earliest 'quality-of-life' upgrades players notice, often prompting a full factory redesign.