A melting furnace is a type of tool used to heat materials, usually for an industrial application. They generally differ in terms of the types of materials they can heat, the temperatures they can generate, and how they function. Some of the most common types are cupola furnaces, electric arc furnaces, induction furnaces, and crucible furnaces.

The furnace has been used by people for a very long time. The earliest furnace is believed to have originated with the Indus Valley Civilization of the Indian subcontinent, and has been dated to somewhere between 2500 and 1800 BC. The melting furnace is an industrial version of this concept, and is typically used for the production of specific materials, or as a heat source.

Some industrial scholars consider the cupola furnace to be the most historically popular form of melting furnace for ferrous materials. This device is comprised of a vertical shaft furnace, resembling a smoke stack. The inside is usually lined with refractory bricks. Air blowing nozzles, used to increase heat, can also be found inside the shaft. The cupola furnace can be used for various tasks, such as producing liquid ore and melting cast iron or bronzes.

Electric arc furnaces are generally employed to re-melt steel scrap. Smaller units may also be used for producing cast-iron products. As the name implies, this model uses an electric arc to generate heat. The arc creates an electrical breakdown of gas that engenders plasma discharge. Inside the furnace unit, material is put in direct contact with the arc, which, in some units, can reach temperatures of up to 3275° Fahrenheit (1800° Celsius).

The induction furnace is generally used for melting both ferrous and non-ferrous alloys. It usually employs a water-cooled, copper helical coil, into which a crucible is installed. When alternating current passes through the coil, the crucible is heated. This model is generally praised for its energy efficiency and the lack of pollution it causes. Most iron foundries now use the induction furnace instead of the cupola furnace because of these advantages.

The crucible furnace is considered to be the oldest type of melting furnace. Its basic design consists of a refractory crucible, into which the material to be heated is placed. The material is then heated from outside the crucible wall. Gas-fired versions of this often use a burner to generate heat, while electric models use heating elements.