Abstract: A thermostat for a HVAC system with visual display of status and operating condition. The thermostat has a power switch to select one of Heater and Cooler for the HVAC system, a light sensor (200) to sense ambient lighting, a temperature sensor (210) to sense ambient temperature, a manual temperature switch (260) to set a desired temperature for the room, a control circuit (220) to select a preferred temperature based on selection of the power switch, an illuminating outer cover (110), which at least partially covers the outside of the thermostat, which displays one of Blue and Red colors according to selection of the power switch and the ambient lighting, and a plurality of LED displays (140) arranged on a display face of the thermostat, to display one arrangement of the LEDs based on a difference between the preferred temperature and the ambient lighting.