Predicting building energy requirements

Abstract This paper is concerned with methods of predicting the thermal performance and energy consumption of buildings. The advantages and drawbacks in practical office situations of both approximate methods and the more precise computer methods are discussed. The widespread use of the computer for these calculations will be necessary for implementation of a National Energy Conservation Standard for building design. The new ASHRAE Standard 90–75 essentially requires such computer methods. A case study carried out for the State of California in an effort to determine the practicality of energy budgets is discussed. The outputs of four proprietary energy programs for the same two buildings are compared and found to be remarkably different. The need for an ASHRAE-endorsed public domain computer program is discussed.