Abstract: An electric furnace comprised of an outer casing, a support casing and a heater casing, the outer casing has a substantially rectangular cross-section with air inlet openings formed in the lower portion of the back wall and in the upper portion thereof whereas air outlet openings are formed in the lower portion of the front and side walls of the same. The support casing is mounted within and in space relationship with the outer casing and the heater casing is within but spaced from the support casing, both support and heater casings are provided with a circular opening in registry at the upper portion of their back wall.