The present invention involves calibrating a control system to enable resistance-based control of a heat tracing circuit, that includes characterizing a piece of heat trace to determine a relationship between resistance and temperature, allowing for more precise control. Also described are different methods for practical resistance-based control of a heat trace system. Further described are several methods to monitor heat trace: including methods to enhance monitoring capabilities using a system operating model; comparison to historical operating data; and inclusion of information from external sources. Also provided is a method by which a piece of heat trace of unknown length and power factor can be controlled using the resistance-based method when other system information is available.