This invention provides a heat alarm apparatus comprising a housing (16) defining a body, a sensor mounting panel (22) located on said body and a heat sensor (12) extending from said sensor mounting panel (22). A control circuit (32) is configured to detect a temperature rise at the heat sensor (12) and output an alarm signal in response thereto. At least the surface (22A) of the sensor mounting panel (22) from which the heat sensor (12) extends is a dark colour.
