Building environmental control systems are disclosed which comprise one or more prefabricated temperature sensing and control panels in operable communication with a system control unit, an air handling system, and a heating and/or cooling utility supply system. The panels are configured to constitute a portion of the sheathing of a building or an internal partition. According to some embodiments, the panels include an outer wall and an inner wall defining an inner space therebetween in which is situated a heat exchanger and a temperature sensor. Each panel comprises an inlet to admit an air stream into its inner space and an outlet for discharging the air stream into a space adjacent to the inner wall after having been thermally conditioned by the heat exchanger.