Patent ID: 8630742

Claim:
A thermostat, comprising: a housing; memory; and a processing system disposed within the housing, the processing system being in operative communication with one or more temperature sensors to determine an ambient temperature, and in operative communication with a heating, ventilation, and air conditioning (HVAC) system to control the ambient temperature according to an HVAC schedule stored in said memory, the HVAC schedule including a first setpoint characterized by a first setpoint temperature and a first setpoint time, the HVAC schedule including a second setpoint characterized by a second setpoint temperature and a second setpoint time, the first setpoint time and second setpoint time defining a first time interval therebetween, said processing system being configured to control the HVAC system to precondition the enclosure during at least a part of said first time interval such that the ambient temperature reaches substantially said second setpoint temperature by said second setpoint time, the processing system including a first processor characterized by at least a relatively high electrical power-consuming first mode of operation and a relatively low electrical power-consuming second mode of operation, wherein the processing system controls the HVAC system to preconditioning the enclosure by: during said first time interval, entering into said first mode of operation to process the second setpoint temperature in conjunction with first information derived from a historical record stored in said memory of previous heating and cooling cycles for said HVAC system as controlled by the thermostat to compute a set of preconditioning criteria information (PCI) representative of time and ambient temperature conditions for which the preconditioning should be performed; storing the set of PCI in said memory; subsequent to said storing the set of PCI in said memory, entering into said second mode of operation; while in said second mode of operation, comparing a current time and current ambient temperature against said PCI to determine whether to enter into a preconditioning state; and entering into said first mode of operation and into said preconditioning state upon a determination that the PCI criteria are satisfied.