IT IS INTENDED PRIMARILY AS A RESOURCE DOCUMENT FOR RESEARCHERS AND ANALYSTS WHO ARE CONCERNED WITH THE DESIGN AND EVALUATION OF SOLAR HEATING AND COOLING SYSTEMS FOR BUILDINGS. FOCUS IS ON ACQUISITION, MAINTENANCE, AND OPERATION COSTS OVER THE LIFE OF A SOLAR HEATING AND COOLING SYSTEM AS COMPARED WITH THOSE FOR A COUNTERPART CONVENTIONAL SYSTEM. THE PAPER IDENTIFIES RELEVANT COSTS, DISCUSSES DATA COLLECTION REQUIREMENTS, ILLUSTRATES THE DISCOUNTING OF COSTS, DEVELOPS GENERALIZED LIFE-CYCLE COST AND BENEFIT-COST MODELS, SETS FORTH TECHNIQUES FOR DEVELOPING MODELS FOR UNIQUE PROBLEMS, AND DISCUSSES HOW THE EFFECTIVE LIFE-CYCLE COSTS TO THE OWNER OF A SOLAR-EQUIPPED BUILDING WOULD BE ALTERED BY CURRENT TAX LAWS, INSURANCE, AND GOVERNMENTAL INCENTIVE PROGRAMS. ASSUMPTIONS REGARDING THE DISCOUNT RATE, THE PERIOD OF ANALYSIS, AND THE RATE OF PRICE ESCALATION IN NONRENEWABLE ENERGY SOURCES. THE PROBLEM OF MAKING COST-EFFECTIVE TRADEOFFS AT THE DESIGN STAGE, INCLUDING TRADEOFFS AMONG COMPONENTS OF SOLAR SYSTEMS, IS DISCUSSED AT LENGTH. ELEMENTS EVALUATED INCLUDE THERMAL STORAGE CAPACITY VERSUS COLLECTOR SIZE; THE PROPORTION OF HEATING AND COOLING TO BE PROVIDED BY THE SOLAR AND AUXILIARY SUPPORT SYSTEMS; AND ENERGY CONSERVING MEASURES VERSUS HEATING AND COOLING LOADS. FOR ILLUSTRATION PURPOSES, THE PROCESS OF FINDING THE ECONOMICALLY EFFICIENT COMBINATION OF BUILDING ENVELOPE AND INTERNAL SPACE CONDITIONING SYSTEM WHICH WILL SATISFY USER REQUIREMENTS IS ANALYZED. TABULAR DATA AND A BIBLIOGRAPHY ARE INCLUDED. (MRK)