Electricity consumption in Iran has a high growth rate. It is important to analyze reasons of this phenomenon by a proper model that can include all affective factors. Based on the system approach, the two physical factors of energy, i.e. power and time, have to be investigated separately. There are so many models to predict the energy demand as well as other models studying the peak load growth. Meantime, there are a few researches on the average time of electricity consumption. This paper proposes a model on one of the two components of the Electrical Energy Demand: the Power and the Time, to investigate how each of the factors like climate, income and price affects energy consumption. This paper tries to separate long – run and short – run factors by focusing on a model for the latter. Considering various combinations of these factors in company with different types of nonlinear relationship, a nonlinear model is constructed to show how the average daily consumption time of the whole simultaneous peak load at the country changes with the climate, economic and/or social factors. For the variety of different combinations of these factors, also different possible candidate nonlinear functions, a vast number of models are analyzed and surveyed. Then a set of selected models is introduced and the best one is chosen via a fuzzy decision-making process. The winner model shows that besides deviations of the weather temperature from a certain moderate climate, any changes in the relative energy conveyors prices, also the per capita income will influence the time that an electrical device is used averagely during a day.