Reducing energy usage by a monitor includes a map manager between a monitor interface and a processor that divides a display area of a monitor into areas and stores display information in a staging area. The map manager distinguishes an active window selected by a user from the remainder inactive, unselected areas of a display, and further determines a used subset of areas within the active window distinguished from the remainder unused areas as a function of a user preference. Accordingly, the map manager drives the monitor at each of the used area active window areas with the processor display information stored in the staging area at a normal luminance specified by the processor display information, and at each of the remainder unused, inactive and unselected areas of the total display area at a reduced luminance lower than the specified normal luminance.