Pilot Study on the Subjective and Objective Comprehensive Evaluation of Thermal and Moisture Comfort Performance of Cold-proof Boots

Objective Cold protective boots are typically constructed with impermeable or semi-permeable materials and feature enclosed structures. In low-temperature environments, this design inhibits the evaporation of foot sweat, causing relative humidity in the shoe cavity to reach saturation. Condensed sweat wets the shoe materials, leading to increased heat loss and disrupted thermal homeostasis, which reduces thermal-humidity comfort. This study aimed to enhance the thermal-humidity comfort of cold protective boots by designing a new model with optimized material combinations, and to evaluate their insulation efficiency, moisture management, and overall thermal-humidity comfort in low-temperature environments compared to traditional boots.

Methods The 17-type cold protective boot served as the control group. Through the osculating value method, various material combinations were evaluated for thermal-humidity comfort. The experimental boot was constructed using microfiber synthetic leather as the outer layer, aerogel as the insulation layer, and Coolmax as the moisture-wicking layer, while maintaining the same appearance as the 17-type boot. The thermal resistance of both boots was measured using a thermal foot manikin to compare their insulation performance. In a climate chamber, three temperature conditions (0 ℃, −5 ℃, −10 ℃) were simulated. Subjects wore each boot type in the chamber, with sensors recording in-shoe temperature and relative humidity. Subjective evaluations of dampness and warmth were conducted using 4-point and 7-point Likert scales, respectively. Moisture absorption of insoles and socks was quantified by comparing their weights before and after the test.

Results The aerogel boot exhibited an average thermal resistance of 0.203 m²·℃/W and weighed 1 kg per boot, compared to 0.196 m²·℃/W and 1.2 kg for the 17-type boot. At all temperatures, the aerogel boot maintained 2−4 ℃ higher in-shoe temperatures across all regions. Although the relative humidity was slightly higher in the aerogel boot, the average moisture absorption of insoles and socks was 1.5 g, significantly lower than the 17-type boot’s 2.89 g. Subjective assessments showed higher warmth scores and lower dampness scores for the aerogel boot, indicating superior thermal-humidity comfort.

Conclusions  (1) Aerogel insulation significantly improves thermal resistance while reducing boot weight. (2) Coolmax lining effectively enhances moisture-wicking in low-temperature environments, improving subjective comfort. (3) Objective measurements and subjective feedback should be combined to evaluate thermal-humidity comfort, as perceived dampness does not always correspond to high-sweat regions.