An illumination maintenance system for maintaining a desired illumination profile in a space throughout at least a portion of a day where the illumination sources include daylight and artificial light, the system comprising: a first sensor (140,145) for sensing an illumination level in at least a portion of the space; at least one electrically controllable window treatment for at least one opening for allowing daylight into the space, the window treatment selectively altering the amount of daylight entering the space through the opening; a plurality of electric lamps providing artificial light to supplement the daylight illumination of the space; the electric lamps being dimmable and being arranged in a plurality of zones in the space, the zones defining predefined volumes of the space, each zone having at least one lamp; a control system controlling the at least one window treatment and the dimming levels of the plurality of electric lamps to maintain the desired illumination profile in the space, the at least one lamp of each zone being controlled to a dimming level to achieve a desired illumination level in the respective zone according to the desired illumination profile; the control system controlling the plurality of electric lamps to adjust the dimming level of each lamp to achieve the desired illumination profile and compensate for the daylight illumination in the space throughout at least the portion of the day; the control system adjusting the at least one window treatment in the event of sun glare through the opening to reduce the sun glare; wherein the dimming level of each lamp is selected by the control system from one of a plurality of lighting presets, each preset comprising a combination of dimming levels of the at least one lamp in each zone and wherein the control system adjusts the electric lamps toward a preset that will result in an appropriate supplementing of the daylight illumination to achieve the desired illumination profile in the space; and wherein the control system stops varying the dimming levels of the lamps and the adjustment of the window treatment when the desired illumination profile is achieved within a predefined tolerance. a first sensor (140,145) for sensing an illumination level in at least a portion of the space; at least one electrically controllable window treatment for at least one opening for allowing daylight into the space, the window treatment selectively altering the amount of daylight entering the space through the opening; a plurality of electric lamps providing artificial light to supplement the daylight illumination of the space; the electric lamps being dimmable and being arranged in a plurality of zones in the space, the zones defining predefined volumes of the space, each zone having at least one lamp; a control system controlling the at least one window treatment and the dimming levels of the plurality of electric lamps to maintain the desired illumination profile in the space, the at least one lamp of each zone being controlled to a dimming level to achieve a desired illumination level in the respective zone according to the desired illumination profile; the control system controlling the plurality of electric lamps to adjust the dimming level of each lamp to achieve the desired illumination profile and compensate for the daylight illumination in the space throughout at least the portion of the day; the control system adjusting the at least one window treatment in the event of sun glare through the opening to reduce the sun glare; wherein the dimming level of each lamp is selected by the control system from one of a plurality of lighting presets, each preset comprising a combination of dimming levels of the at least one lamp in each zone and wherein the control system adjusts the electric lamps toward a preset that will result in an appropriate supplementing of the daylight illumination to achieve the desired illumination profile in the space; and wherein the control system stops varying the dimming levels of the lamps and the adjustment of the window treatment when the desired illumination profile is achieved within a predefined tolerance.