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 for sensing an illumination level in at least a portion of the space, at least one 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, a plurality of electric lamps providing
artificial light to supplement the daylight illumination of the space; the electric lamps being dimmable, a
control system controlling the at least one window treatment and the plurality of electric lamps to maintain the desired illumination profile in the space, the
control system controlling the plurality of electric lamps so that the dimming level of each lamp is adjusted to achieve the desired lighting profile and compensate for the daylight illumination in the space throughout at least the portion of the day; and the
control system further operating to adjust the window treatment in the event of sun glare through the opening to reduce the sun glare and such that when the desired illumination profile within a defined tolerance is achieved, the control
system stops varying the dimming levels of the lamps and the adjustment of the at least one window treatment.