This work has the purpose of evaluating the use of the technique Conditional Demand Analysis - CDA, which is a methodology that segregates the consumption of electric energy (on this work about the residential sector) is its parts per equipment and per final use through the Robust Regression, in counterpart of using the classic regression, in the estimation of the electric energy consumption for final use on the residential sector. For this purpose analyses will be made using the multiple linear regression and also analyses using the robust regression (robust estimators). The two analyses will be made for comparing the classic method Squared Minimums Usual - MQO, which is not the ideal one because the data violates the requirements for using this kind of method, and the robust method, less sensible to detours of the requirements.