Household appliance (1) for cooking and/or baking food stuffs or bakery ware (2) comprising a heatable cavity (3) for placing the food stuffs or bakery ware (2), an access door (4) for accessing the cavity (3), a compartment (5) located exterior of said cavity (3), said compartment being in fluid communication with said cavity (3) by at least one duct (6), a control unit (10), at least one first sensor (8) located in the compartment (5) and being connected to the control unit (10), and wherein the at least one first sensor (8) is capable of measuring a first input value in said compartment (5), and at least one second sensor (9) capable of measuring a second input value, wherein said second input value is a temperature value wherein said control unit comprises a matrix of humidity index values, said matrix being deposited in said control unit (10), and wherein said control unit (10) is capable of correlating said input value of said at least one first sensor (8) to a humidity index value from said matrix.