The present work evaluates the feasibility of the conversion of a tempering electric furnace by forced convection in a dual electricity-natural gas furnace. By proposing to perform a conversion of a heat treatment furnace towards a dual system, it is intended to give more flexibility in the operation of an equipment that must stay working for 24 hours a day. By having two alternatives for heat generation, it can be avoided a non-programmed stop in the process of the furnace due to problems in the electricity supply, which could result from unexpected failures in the National Interconnected System or energy crisis such the one occurred at the beginning of 2007 in Colombia. The methodology for conducting this study included an energy assessment of electric furnace in its current state, the proposal of a new design that incorporates a non-premixed natural gas burner and the assessment of the heat transfer to the load using computational fluid dynamics simulations, as well as its energy efficiency and emission of pollutants. The results of this study allowed to determine the efficiency of the electric tempering furnace, the viability of adaptation of a gas burner into the furnace and the estimation of emissions resulting from the combustion, under different operating parameters