The main trends in energy saving in buildings - theory and practice in the USSR.

The paper reviews some problems of theory and practice of energy conservation in buildings. The necessity for a policy of energy
saving in the country is substantiated. The problems of energy conservation are studied in terms of mathematical simulation of a building as a single energy-consuming system. The method is given of economic optimization of the total thermal resistance value of the envelope, which is the basis of the Soviet Building Code on Heat Engineering. The Soviet Code provisions are compared with those of other countries. Some ideas on optimization of window structures are presented.