Abstract: A room thermostatic control providing for automatic power defer, i.e. modification of load consumption of electrically energized heating and cooling systems during intervals when there is a peak load demand on the electrical supply system. During power defer ambient indoor temperature is controlled by set point adjustment to minimize discomfort, e.g. by pre-boosting, by ramped temperature deferral at controlled rates, and thereafter by ramped recovery at controlled rates to the reference, i.e. desired, temperature. The preferred embodiment has normal and night set back reference temperature potentiometers and ambient indoor temperature sensing circuits providing, respectively, analog reference and analog indoor signals. Digital set point signals are derived and compared with the analog indoor signal to actuate relays controlling operation of the heating and cooling means, e.g. compressor and auxiliary resistance heating. A circuit sensing external conditions, e.g.