Inorganic phase change materials, PCMs, encapsulated in rigid plastic panels are available for passive solar heating applications in trombe walls and sunspaces. Performance of the panels has been tested in several systems. Accurate performance testing of PCM walls has been conducted in a full-scale calibrated hot box. Additional testing was conducted in unoccupied test houses during the winter season of 1983. This paper discusses the results of the calibrated hot box study and the performance of two unoccupied test houses, one of which had a PCM trombe wall. The calibrated hot box data include accurate measurements of heat flux during the discharge cycle of integrated trombe wall systems containing the PCM panels. In the test house program, energy consumption in the side-by-side mini test houses and heat flux measurements are evaluated.Units: Dual