E-textiles for wearable applications utilize textile structures, including knitting, weaving, and nonwoven fabrics due to their excellent flexibility, breathability, and compatibility with the human body. Herein, we report the influence of knitting structural parameters such as knit, float, and tuck and diverse environmental conditions on the performance of the developed knit-based heating pad. Stainless steel and low-twisted cotton yarn were used to develop four different types of knit-based heating pads, including 3R (three courses of knit), 3T (three courses of tuck), 3F (three courses of float), and FTF (first course float, second course tuck, and third course float). In comparison to the 3R structure, the surface temperature of the 3F and FTF knitted heating pads increased by 38.2 and 23%, respectively. The 3F knitted structure also exhibited the least temperature change due to float in the structure, which is 10.60 at a 60% extension level. The effect of relative humidity levels of 20, 40, 60, and 80% and surrounding temperatures of 20, 30, 40, and 50 °C with and without airflow on the efficiency of the 3F heating pad is investigated. In addition, a lab-based prototype heating pad with a distinct covering fabric including single jersey, rib, and interlock was developed for the alleviation of neck and wrist pain.
