An electric warming blanket (100; 200), comprising: a flexible conductive fabric heater including a first side and a second side; a first layer of water resistant material disposed over the first side of the heater, being un-adhered thereto, and forming an outer surface of the blanket when the blanket is draped over an object or a person to be warmed; and a second layer of water resistant material disposed over the second side of the heater, being un-adhered thereto, and forming an inner surface of the blanket, adjacent to the object or the person, when the blanket is draped thereover, the first layer of water resistant material coupled to the second layer of water resistant material about a perimeter of the heater to form a substantially hermetically sealed space for the heater; a layer of thermal insulation disposed between the first side of the heater and the first layer of water resistant material; a temperature controller; a temperature sensor assembly coupled to the heater and the controller; and an electric power source coupled to the heater and to the temperature controller, characterized in that: the flexible conductive fabric heater has at least one of the first and second sides having a surface area and a substantially uniform watt density output across the surface area when the fabric heater is electrically powered; the temperature sensor assembly comprises a temperature sensor (21; 121), the temperature sensor providing input of a temperature over a portion of the surface area of the heater surrounding the temperature sensor to the temperature controller; and the power source is controlled to provide the substantially uniform watt density output for the heater according to a temperature sensed by the temperature sensor such that when a first portion of the heater including the temperature sensor is in conductive contact with the body and a second portion is not in conductive contact with the body, the second portion has a higher equilibrium temperature than the first portion. a flexible conductive fabric heater including a first side and a second side; a first layer of water resistant material disposed over the first side of the heater, being un-adhered thereto, and forming an outer surface of the blanket when the blanket is draped over an object or a person to be warmed; and a second layer of water resistant material disposed over the second side of the heater, being un-adhered thereto, and forming an inner surface of the blanket, adjacent to the object or the person, when the blanket is draped thereover, the first layer of water resistant material coupled to the second layer of water resistant material about a perimeter of the heater to form a substantially hermetically sealed space for the heater; a layer of thermal insulation disposed between the first side of the heater and the first layer of water resistant material; a temperature controller; a temperature sensor assembly coupled to the heater and the controller; and an electric power source coupled to the heater and to the temperature controller, characterized in that: the flexible conductive fabric heater has at least one of the first and second sides having a surface area and a substantially uniform watt density output across the surface area when the fabric heater is electrically powered; the temperature sensor assembly comprises a temperature sensor (21; 121), the temperature sensor providing input of a temperature over a portion of the surface area of the heater surrounding the temperature sensor to the temperature controller; and the power source is controlled to provide the substantially uniform watt density output for the heater according to a temperature sensed by the temperature sensor such that when a first portion of the heater including the temperature sensor is in conductive contact with the body and a second portion is not in conductive contact with the body, the second portion has a higher equilibrium temperature than the first portion. the flexible conductive fabric heater has at least one of the first and second sides having a surface area and a substantially uniform watt density output across the surface area when the fabric heater is electrically powered; the temperature sensor assembly comprises a temperature sensor (21; 121), the temperature sensor providing input of a temperature over a portion of the surface area of the heater surrounding the temperature sensor to the temperature controller; and the power source is controlled to provide the substantially uniform watt density output for the heater according to a temperature sensed by the temperature sensor such that when a first portion of the heater including the temperature sensor is in conductive contact with the body and a second portion is not in conductive contact with the body, the second portion has a higher equilibrium temperature than the first portion.