The Furnace is one of the most iconic items in RUST. This player-deployable smelting item is one of the few base accessories players must have to progress. It acts as one of the first hurdles players aim to overcome on wipe day due to its Low-Grade Fuel requirement.
The Furnace is used (along with wood) in the smelting of High-Quality Metal Ore, Metal Ore, and Sulfur Ore to convert them to their usable forms. Players may deploy them on floors and other flat surfaces with proper Tool Cupboard authorization.
Prior to more recent updates, furnaces had also been a general-purpose storage container since it had a small, 6-slot storage capacity. Players could quickly toss some of their inventory into a nearby furnace and head back out of the base without a complaint from the furnace. This feature is no longer possible with the Furnace UI upgrades of more recent updates.
In addition to their other functions, standing next to a lit furnace also produces the same effect as a lit Camp Fire, providing 50% default comfort and warming a player considerably. They are only obtained through crafting and are a default blueprint. You cannot cook food in them, no matter how many times you try.
Furnaces are a commonly-skinned item in RUST and many skins have been released to accommodate this popularity.