How to Maintain Semiconductor Heater for Stable Day-to-Day Heating
https://advanced-electric.hexaforgey.com/posts/how-silicone-heater-works-and-where-it-fits-in-modern-equipment
Many heating problems look like a power problem at first. In practice, the cause may be contact, heat loss, sensor position, or poor fit. A semiconductor heater works best when these parts are planned together