This paper presents a comparative simulation study of three feedback-control strategies for regulating air temperature in a laboratory-scale infant incubator. A first-order thermal model is obtained from a lumped energy balance and used to design a practical proportional-integral-derivative controller with derivative filtering, an internal-model-control-based proportional- integral controller, and a linear-quadratic-integral controller. The simulations include actuator saturation, a heat-loss disturbance beginning at 5 s, plant-parameter variation, and measurement noise. Performance is evaluated by rise time, settling time, overshoot, integral squared error, integral time-weighted absolute error, and total variation of the heater command. Under nominal conditions, the LQI controller produces the fastest response and the lowest tracking indices, while the filtered PID provides a less aggressive practical compromise. The IMC-PI controller has the smoothest and most noise-insensitive behavior but is slower. The results provide a transparent controller-selection framework for an educational incubator-control design; they are not a clinical certification or a substitute for safety testing on medical equipment................. Keywords:..............Infant incubator, Temperature regulation, PID, IMC, LQI, Disturbance rejection, Robustness.