Energy-cost allocation systems apportion heating and/or cooling costs among the individual apartments in centrally-metered buildings based on various measures of relative energy use or thermal comfort. The most commonly used systems measure one or more parameters related to the thermal output of the terminal elements. In this paper, a new method for energy-cost allocation purposes was developed and studied. Taking advantage of the theory of frequency response, the individual apartments' energy consumption for cooling in summer may be calculated using several parameters that include indoor and outdoor temperatures and the values of solar radiant-intensity. Experiments were done in this study, which indicates that the method of frequency response is fairly good in calculating the energy use of cooling. (C) 2004 Elsevier Ltd. All rights reserved.