During the COVID-19 pandemic, the widespread use of face masks has become standard practice, raising questions about their impact on work efficiency. This paper examines the relationship between face mask use and subjectively assessed productivity and well-being of people in the smart educational building. A multi-stage approach was used: from hierarchical cluster analysis (HCA) and principal component analysis (PCA) to advance general linear modeling (GLM). Initial cluster analysis revealed significant data segmentation resulting from illuminance, but statistical modeling demonstrated that lighting does not determine work efficiency. A key finding is the dominant effect of ambient temperature on both parameters (p < 0.01). After statistically isolating the influence of microclimate, mask use demonstrated a significant negative impact on well-being (p = 0.045), but did not significantly impact productivity (p = 0.125). The results suggest high professional adaptation of people who maintain performance despite perceived discomfort and indicate the priority role of thermal regulation in optimizing work in personal protective equipment.