This work presents an optimization model aiming to obtain the lowest final value of energy billing for residential and industrial users without altering the final electrical demand, providing flexibility and active participation, by means of changing customer consumption habits and including storage systems with the injection of photovoltaic systems. The presented model is based on Time of Use demand response methodology and uses hourly tariff defined by CREG in Resolution 015/2018, obtaining rates at three different levels to enable flexible demand scheduling. The proposed methodology allows to minimize energy billing according to the current regulation in Colombia related to hourly tariffs and shows savings of up to 73 % without considering capital expenditure (CapEx).