The maturity and capacity of a business are parameters that are directly associated to its quality and experience. In the specialized field of energy performance, these parameters are a determining factor on the reliability of results. In Chile, a lack of codes, standards or norms on energy simulation, it is of vital importance to have a system that is precise in its predictions. This study is centered on determining the level of uncertainty by analyzing different specialized firms in this field, taking into account their level of experience and internal capacities. We analyzed 32 consulting firms in function of their capacities and experience through a matrix of organizational capacity and maturity adapted to the energy efficiency field. To do this, we proposed the following elements of analysis: type of system used for simulation (static-dynamic), qualification of the staff in charge of each study, certification in national or international standards related to the specialty, use of internal work protocols and the existence of a quality assurance system for their processes. It can be expected that the level of reliability increases with firm maturity due to the ponderation that is assigned to each level. At the same time good performance is assured when there exist objective procedures that sustain internal capacities in such a way that the highest levels of predictability are achieved in an optimized atmosphere complemented with quality assurance systems. This tool can serve as a reference for firms in the project design phase, in such way that they can determine the confidence level of a simulation in function of the specialist's quality and experience.