tl;dr: Wax motors are linear actuators that exploit the 5-20% volume expansion of wax during melting to convert thermal energy into mechanical force, capable of producing up to 4000 N. Compared to solenoids, they offer smooth actuation, resistive (non-inductive) electrical behavior, and can operate passively from ambient heat sources. Common applications include front-load washing machine door locks, dishwasher detergent dispensers, thermostatic mixing valves, hydronic zone valves, greenhouse vent controls, and aerospace fluid systems.