An adjustable window awning/light shelf includes a canopy attached to support elements installed on both sides of the window. The support elements are engaged with vertical drive screws providing for the possibility of moving the canopy up and down. Each drive screw is connected with a common drive shaft. During the cooling season, when the window needs to be shaded, the canopy is disposed at the top of the window. When shade is not required, the canopy is brought down to the bottom of the window by rotating the drive shaft, which in turn rotates the drive screws and moves the support elements with the canopy down. When in the bottom position, the awning performs as a light shelf, reflecting sunlight from its top surface into the window and increasing the amount of sunlight and solar heat entering the building through the window.