System and methods for controlling and optimizing coolant system parameters in a fuel cell system to obtain a requested cabin temperature in a fuel cell vehicle are presented. A method for managing a temperature in a vehicle cabin may include receiving an indication relating to a desired vehicle cabin temperature and a plurality of measured operating parameters. Based on the measured operating parameters, a projected output temperature of a cabin heat exchanger may be estimated. A determination may be made that the projected output temperature of the cabin heat exchanger is less than the indication. Based on the determination a fuel cell coolant parameter may be adjusted.