The paper is devoted to the analysis of possibility for construction of low energy buildings with envelopes controlled for minimization of energy consumption by air conditioning systems. It describes the possibilities to reduce energy consumption of large public buildings mainly in summer time when there are the highest electricity demands for cooling. The paper gives a complex mathematical model for controlled envelope’s thermal resistance depending on outdoor parameters. It proposes constructive suggestion to create buildings whose walls, roofs and glassed surfaces have changeable thermal characteristics and methodology of control for separate elements (double skin facades, multiple films on windows, ventilated curtain walls, automated Venetian blinds). Building energy performance simulation models during the whole year allow choosing optimal characteristics of building envelope on the basis of annual heat consumption. The paper analyses the impact of building envelope thermodynamic characteristics on the parameters of supply air in air conditioning systems. It describes the change modes of thermal resistance, resistance to water vapour transfer and resistance to solar radiation considering the different states of inside and outside air conditions