Abstract: A temperature controlling system (10) is normally controlled by a thermostat that is superseded by a remotely controlled thermostat (21) in response to a remote control signal transmitted over telephone lines that retains control for eight hours established by an eight-hour clock (14). A response oscillator with warning thermostat (13) provides an answering signal indicating that the superseding thermostat is exercising control over the temperature controlling system of pitch which is varied to indicate control and distinctly lower when the warning thermostat indicates the temperature is less than a predetermined value.