Environmental condition controller and method for controlling an environmental condition in an area of a building. The controller stores a predictive model generated by a neural network training engine, and a previously calculated environmental condition adjustment value (yn−1). The controller receives an environmental condition target value (xref), and an environmental condition measured value (x). The controller recursively calculates an environmental condition adjustment value (yn) by executing a neural network inference engine using the predictive model for inferring the environmental condition adjustment value (yn) based on the previously calculated environmental condition adjustment value (yn−1), the environmental condition target value (xref), the environmental condition measured value (x), and an adaptive proportionality value (k). The controller also generates and transmits a command based on the environmental condition adjustment value (yn). The controller further stores the calculated environmental condition adjustment value (yn) as the previously calculated environmental condition adjustment value (yn−1).