What is Predicted Percentage Dissatisfied (PPD)

This chapter proposes an approach to thermal comfort that increases occupant pleasure and reduces energy use by connecting architecture's material and environmental dimensions. Today's dominant thermal comfort model, the predicted mean vote (PMV), calls for steady-state temperatures that are largely unrelated to building design decisions. A more recent alternative approach, the adaptive thermal comfort (ATC) model, ties comfort to outdoor conditions and individual experience. Yet reliance on HVAC technology to provide building comfort hampers how such ideas are integrated into building design. This chapter outlines the historical background of the PMV and ACT models to understand the current status of thermal comfort research and practice. It then uses four recent buildings to outline how the insights of adaptive comfort research can be translated to bespoke comforts through spatial, material, formal, and other design strategies.