A heating system is configured to optimize the speed and accuracy of the system in achieving various ambient air temperature setpoints, by modulating the heated water supply water setpoint to optimize the slope of the system's response curve. Optimized response curves are automatically determined by analyzing differences between ambient air temperatures over time in response to modulated supply water temperatures as they are reset upward or downward to achieve response times prioritized for improved occupant comfort. The controller of the heating system calculates a temperature slope, and adjusts the supply water setpoint to increase/decrease the speed of ambient temperature rise to achieve a desired slope.