A method for forming a glass sheet with reduced inclusions is disclosed. The method includes flowing molten glass over converging forming surfaces of a forming body positioned within an enclosure. The forming body is heated with a plurality of heating elements separated from the forming body by an inner wall of the enclosure. The temperature T2 at the bottom of the forming body is decoupled from the temperature T1 at the top of the forming body by an insulating thermal barrier positioned between two adjacent heating elements of the plurality of heating elements such that a change in T2 does not cause a substantial change in T1.