An acceleration sensor for a household device which serves for levelling the appliance and also for weighing the material introduced into the appliance, for example on a laundry unit or crockery and furthermore, in particular for a linen treatment device, for monitoring imbalances. The sensor is based on the principle that a temperature profile, generated by a thermal source, for example, an immersion heater, in a sealed chamber which contains a gas, undergoes a displacement as a result of the acceleration, which is measured by temperature sensors arranged on a flat plate.