An expert-based review of Mean Radiant Temperature across ten research domains at urban and building scales

Mean Radiant Temperature (MRT) has emerged as a critical parameter for evaluating human thermal comfort in built environments and microclimates across the globe. Defined as the uniform temperature of an imaginary enclosure where the radiant heat exchange with the human body matches that of the actual, non-uniform environment, MRT offers a comprehensive representation of radiative thermal exposure. Understanding MRT requires examining its relationship with human thermal indices, long-term fluctuations in outdoor settings, and impacts on human health and climate change patterns. This is a relevant topic for urban and landscape planners, architects, urban designers and health professionals, with accurate MRT assessment recognized as key to developing thermally comfortable spaces. Precise MRT measurement benefits occupants through improved thermal comfort conditions and energy efficiency. Furthermore, implementing MRT-informed design strategies helps reduce cooling demands, making it more affordable to maintain comfortable indoor and outdoor environments. This 'ten domains contribution' provides an overview of MRT's importance in human thermal comfort assessment, measurement and modelling techniques, relationships with indoor and outdoor environmental characteristics, implications for health studies and exposure during extreme heat events and heat waves, optimization strategies for buildings and HVAC systems, and future perspectives in the context of global to local climate change.