METHODS OF CALCULATING THE ENERGY CONSERVING FEATURES OF BRICK INCLUDING HEAT GAIN AND 'U' VALUE CALCULATIONS--THE MEASURE OF HEAT TRANSFER RESISTANCE OF THE WALL UNDER STEADY-STATE CONDITIONS--ARE DESCRIBED. IN ADDITION, ENERGY SAVED IN BRICK PRODUCTION, WASTE DISPOSAL, TRANSPORTATION, AND REUSE IS EXAMINED. THE ARTICLE FURTHER DISCUSSES DRAWBACKS OF THE TRADITIONAL APPLICATION OF THE STEADY-STATE OR STEADY-PERIODIC HEAT FLOW CONCEPT WHICH DOES NOT MEET THE NEEDS OF THE BUILDING PROFESSIONAL WHO MUST SELECT OR DESIGN MORE THAN ONE HEATING OR COOLING SYSTEM. HEAT GAIN CALCULATIONS FOR THE COOLING CYCLE BY APPLICATION OF A TOTAL EQUIVALENT TEMPERATURE DIFFERENTIAL (TETD) ARE DISCUSSED AS ARE PROBLEMS OF CALCULATING HEAT LOSS DURING THE HEATING CYCLE TO CLOSELY APPROXIMATE THE TRUE PERFORMANCE OF HEAVY MASONRY WALLS. A LIST OF TECHNICAL DEFINITIONS IS APPENDED AND TABLES PRESENTING DATA FOR WEIGHT, TIME LAG, AMPLITUDE DECREMENT FACTORS AND HEAT GAIN, AS WELL AS 'U' VALUE CALCULATIONS, ARE GIVEN. (AOP)