If you have an attached garage mount the thermostat on the common wall between the garage and the house and away from the heated airflow.
Install thermostat wall heater.
In a detached garage mount it on the wall below the heater.
It s easiest to mount a thermostat used with a wall heater in the same stud cavity on the opposite side of the stud about five feet above the floor.
Mount wall thermostats used with a baseboard heater across the room from the heater.
Mount the thermostat base on the wall using the screws included with the thermostat.
If you have two or more heaters in a large room place the thermostat in a central location.
Connect the low voltage wires to the appropriate screw terminals on the new thermostat base if your connections do not match consult the installation diagram in the new thermostat s owner s manual.