The average predicted percentage dissatisfied (APPD) is an appropriate means of expressing the thermal comfort conditions of a heated space. Therefore, APPD provides a basis for comparisons of various heating system designs. In order to perform this study, the PSU-MRT computer program was expanded to include two subroutines. These subroutines determine the APPD of the occupied zone and calculate, by two different methods, the heat loss for a given conditioned space. Following the modifications to PSU-MRT, the program was used to evaluate certain aspects of the currently accepted design methodology for low-temperature radiant heating applications. Recommendations concerning optimal radiant panel location and the prediction of space-heating loads were analysed. The results of this study suggest that revisions to the current design methodology may be necessary. Correction factors for conventionally determined heat loss values and guidelines for panel location in limited cases are provided.

KEYWORDS: radiant heating, thermal comfort, computer programs, calculating, location, heat loss, radiant panels, space heating, heat load, designing.