A classification scheme for exploring the role of wearable thermal PECS in a changing climate

Global warming due to climate change is increasingly challenging human thermal comfort in both indoor and outdoor environments. Extreme weather events, such as heatwaves and cold snaps, are expected to become more frequent and intense, posing serious threats to human well-being and health. These impacts are particularly critical for vulnerable populations, including outdoor workers and low-income households. This highlights the need for occupant-centric, energy-efficient, and resilient solutions that are both accessible and practical for everyday use. Wearable Personal Environmental Control Systems (PECS) for thermal management represent a promising solution to simultaneously mitigate indoor and outdoor thermal stress and reduce energy demand for indoor heating or cooling. By targeting the personal microenvironment, wearable PECS can address individual thermal preferences while relying on relatively low power capacity. Moreover, as portable systems, wearable thermal PECS can seamlessly accompany individuals across indoor, outdoor, and transitional spaces. When equipped with physiological and/or environmental sensing capabilities, wearable thermal PECS not only enhance comfort under dynamic conditions but also offer unique opportunities for the development of advanced Personal Comfort Models by capturing individual responses in real-world settings. In the framework of IEA EBC Annex 87, which overarching goal is supporting the development and market uptake of wearable thermal PECS, this contribution presents a preliminary attempt to establish a coherent classification scheme for such technologies. The proposed scheme is structured around key dimensions identified in the literature, including energy requirements, sensing capabilities, controllability, durability, and invasiveness. These dimensions are discussed in relation to their potential to guide technology design, enable cross-comparison among solutions, and foster standardization within the field. Ultimately, this study contributes to a structured understanding of wearable thermal PECS, highlighting their role as a flexible, low-energy strategy to enhance human resilience against climate change while opening new avenues for research in personalized thermal comfort.