Patent ID: 8141791

Claim:
A thermostat apparatus for determining a present setpoint temperature, the thermostat apparatus for controlling a heating apparatus for heating a conditioned space, the heating apparatus including means for producing heat which includes a first heating apparatus and a second higher output heating apparatus, the second higher output heating apparatus optionally including the first heating apparatus, the second higher output heating apparatus being capable of producing more heat than the first heating apparatus alone; the thermostat apparatus providing a first signal for normal heat intended for turning on the first heating apparatus and a second signal for high heat for turning on the second higher output heating apparatus, the thermostat apparatus also including an occupancy sensor for determining when the conditioned space is occupied and when the conditioned space is not occupied; the thermostat apparatus including means for determining a user desired occupied setpoint temperature for use during periods the conditioned space is occupied; the thermostat apparatus further comprising: A) means for obtaining a value for a maximum allowed temperature recovery time, specified by the user as a parameter describing the maximum desirable period of time allowable for returning the conditioned space to a temperature approximating the user desired occupied setpoint temperature following any period of time during which the present setpoint temperature was reduced due to determining that the conditioned space was not occupied; B) a first control means for turning on the second signal for high heat and during at least a portion of the time while high heat is applied measuring a high heat conditioned space temperature response rate; C) means for calculating an unoccupied setpoint temperature based upon: 1) the high heat conditioned space temperature response rate; and, 2) the maximum allowed temperature recovery time; and, D) means for setting the present setpoint temperature to the unoccupied setpoint temperature when the conditioned space is not occupied.