This paper presents the development of a thermally enhanced frame wall that reduces peak air conditioning demand in residential buildings. A frame wall that integrates a highly crystalline paraffin phase-change material (PCM), via macro-encapsulation, was developed, constructed, and evaluated. This prototype wall is referred to as phase-change frame wall (PCFW). Results from field testing show that the PCFW reduced wall peak heat fluxes by as much as 38%. For a period of several days that included walls facing different directions, the average wall peak heat flux reduction was approximately 15% when PCFWs with a 10% concentration of PCM (based on indoor sheathing weight) were used and approximately 9% when a 20% PCM concentration was used. The average space-cooling load was reduced by approximately 8.6% when 10% PCM was applied and 10.8% when 20% PCM was used. The level of insulation in the PCFWs that were tested was 1.94 m(2)K/W (R-11). Copyright (c) 2005 John Wiley & Sons, Ltd.