Abstract: A steady state thermostat is disclosed which employs a magnetic flux coupling technique to obtain a greater stability in its operation, resulting in a significant reduction in fuel costs. The thermostat includes a temperature sensor operated arm and a temperature setting arm pivotally mounted on a common base pivot. A first magnetic field source is mounted on the first end of the sensor arm coincident with a first axis and a second magnetic field source is mounted on the second end of the sensor arm coincident with a second axis. A first magnetic field sensor is mounted on the first end of the setting arm coincident with the first axis and adapted for proximate positioning with respect to the first magnetic field source when the selected orientation of the setting arm corresponds to the desired ambient temperature being higher in magnitude than the existing ambient temperature.