Electric furnaces provide 2 module slots which make them more flexible for special purposes. The use of electrical power makes them independent from a direct power source, but the huge heating devices take some extra space, which makes the electric furnace slightly bigger than the burner furnaces.
Furnaces are used to smelt resources into usable products for further usage. Therefore furnaces are a key building for developement and automation. Starting with very basic stone furnaces the player can advance through research and replace them with more efficient and faster furnaces later in the game.
