A flexible heating subassembly, that may be incorporated in a heating blanket or any other type of flexible heater, includes a flexible sheet-like heating element, or heater, to which first and second conductive bus bars are coupled, each with a respective first and second row of conductive stitching. A first electrically insulating member is interposed between the first bus bar and the heater and is secured therebetween by the first row of stitching, and a second electrically insulating member is interposed between the second bus bar and the heater and is secured therebetween by the second row of stitching. The first and second insulating members prevent direct electrical contact between respective first and second bus bars and the heater.