The photovoltaic (PV) applications where the dimensioning is effected through the daily energy balance criteria obtained by the estimation of the energy consumption depending on the power and time of use of the electrical apparatus are limited to autonomous PV systems with well-defined end use. Applications where one would like to electrify complex end use, such as office buildings, schools, hospitals, laboratories, residential units, etc., quantifying the daily energy consumption is difficult mainly due to two aspects. First, there will be great number of a variety of electrical appliances and second the proportionate electrical consumption of each one of them is unpredictable. For this reason it is necessary to establish a methodology that permits one to quantify precisely the daily energy consumption pattern to predict the energetic functioning of the PV system whose size may be determined by this procedure. In this work we describe a methodology for the energetic quantification of the installed equipments by using a Power Quality Analyzer to obtain the historical global energy consumption, daily energy consumption (kWh day(-1), kVAh day(-1)) and the energy quality for the dimensioning of the PV system. Copyright (C) 2009 John Wiley & Sons, Ltd.