A comfort control system and method which determines the operating temperature set point for the environment to be controlled, in part by indirectly measuring the mean radiant temperature of the environment. A temperature sensor and relative humidity sensor sense the environment to be controlled and provide electrical signals indicating the sensed values to a microprocessor. A building load monitor either monitors the duty cycle of the heating/cooling system for the environment or senses the difference between the environment temperature and the outside temperature to generate a value indicative of the heating or cooling load on the building. A calculation formula to be stored in the microprocessor factors the selected operating temperature, the building load, the relative humidity, and selected constance. The microprocessor determines the operating set point, compares the set point to the temperature of the environment, and generates a control signal for the heating/cooling system. A method of controlling the comfort of an environment comprises the steps of sensing the air temperature and relative humidity of the environment, monitoring the building load, accessing the selected temperature and selected constant values for use in an operating set point calculation formula, calculating the operating temperature set point, comparing the operating temperature set point with the sensed room temperature, and generating a control signal for the heating/cooling system based on the comparison.