A system and method for controlling a heating, ventilating, and air conditioning (HVAC) system in a dwelling is provided. The system includes a plurality of wireless thermostats disposed throughout multiple zones within the dwelling and operable to control climate conditions in the corresponding zones. The system further includes a primary power source operable to supply power to thermostats for operating in a high-power mode when operatively connected thereto. The thermostats each include a secondary power source operable to supply power to the thermostats for operating in a low-power mode when the corresponding thermostat is not powered by the primary power source. Thermostats operating in the high-powered mode are operable to receive and repeat signals originating from one or more thermostats operating in the low-power mode.