Proposed is a home appliance that includes a reception space configured to receive objects therein; a heater configured to heat the reception space; a door configured to open/close an open surface of the reception space, the door having a viewing window provided at the door; a lamp configured to illuminate an inside of the reception space; a sensor assembly configured to output a knock-on signal based on detecting a user's knock; and a controller configured to turn on/off the lamp based on the knock-on signal output by the sensor assembly, wherein based on a present state of the home appliance corresponding to at least any one of a plurality of preset exceptional situations, the controller is configured to not turn on/off the lamp regardless of the knock-on signal being output.