In this chapter, power consumption and electrical demand in buildings or housing due to the utilization of HVAC systems are shown to be intimately linked to construction materials. This work proposes a methodology of energy management intended to analyze and evaluate actions aimed at saving and efficient use of electric energy of HVAC systems applied to regions with hot and dry climates. The methodology consists of: (1) characterization of local climatology using the concept of degree-hours (DH). (2) Utilization of a Fourier-type mathematical model to calculate hourly temperature using only daily maximum and minimum temperatures as well as an empirical model to compute energy efficiency (EER) of air-cooled air conditioning units. (3) Thermal simulation applying a software developed by the authors based on ASHRAE's Transfer Functions methodology to calculate hourly cooling loads, the adequate sizing of air conditioning equipment and the rate of heat extraction. (4) System analysis, identification of improvement actions, evaluation of viable alternatives of saving and efficient use of energy. The advantage of this proposal is its flexibility because it can be applied to any climatology and easily adaptable to the conditions of energy usage anywhere in the world.