Considering child-specific view factors in human thermal balance

View factors VF in human heat balance calculations are influenced by shape and size, yet existing standards use uniform values for all. Previous research has examined height and weight variations within adult populations, but no studies have investigated children’s view factors. To address this, we created a numerical manikin representing an average 5-year-old boy in the standing posture and one based on the average male participant from Fanger, using a human shape generator. We calculated projected area factors f_p for both numerical manikins using the parallel ray method, calculated VF and created graphical representations as a function of wall dimensions and distances. Our analysis showed significant differences in f_p between the adult and 5-year-old child, with variations up to 22%, significantly higher than those found between adults in the literature. Using adult and child VF in a test scenario, the 5-year-old child’s mean radiant temperature MRT was ∼1 °C higher than the adult’s with radiant floor heating, and ∼0.6 °C higher with a chilled ceiling. This significant MRT difference demonstrates that child-specific view factors should be considered in future thermal comfort calculations for young children.