Glass heat zone control

A refrigerated display case door, comprising:

• a glass panel assembly comprising:
• a first pane of glass and a second pane of glass bounding a sealed space between the first pane and the second pane;
• and
• an electrically conductive coating applied to a surface of the first pane, the electrically conductive coating extending across at least a majority of a viewing area of the first pane;
• a first pair of electrical buses spaced apart from one another and electrically connected to the electrically conductive coating at respective first and second ends of the first pane, the first end positioned at a top of the refrigerated display case door and the second end positioned at a bottom of the refrigerated display case door;
• and
• a second pair of electrical buses spaced apart from one another and electrically connected to the electrically conductive coating at respective third and fourth ends of the first pane, the third and fourth ends being opposite one another and adjacent to the first and second ends;
• and
• a controller configured to supply power independently to the first pair of electrical buses and the second pair of electrical buses, the controller operable to perform operations comprising controlling a voltage level applied to each bus bar to develop different heating zones across the electrically conductive coating.