Patent ID: 8456729

Claim:
A method for automatic daylighting, the method comprising: detecting an interior light illuminance level primarily due to exterior light entering a window into a room; determining whether the room is in a heating mode; detecting whether the room is occupied by people; detecting whether occupants have manually operated an adjustable window covering for the window in the room; detecting an exterior sky condition; calculating an adjustment of the adjustable window covering, such that the adjustable window covering is modulated to i) block direct sunlight from entering the room through the window when the exterior sky condition is a sunny sky state and the room is in a cooling mode, ii) subject to satisfying (i), provides a desired daylighting interior light illuminance level through the window that is within a target daylighting range and provides a desired interior solar heat gain through the window that is within a variable target heat gain range; and automatically adjusting the adjustable window covering based on the calculated adjustment, wherein the adjusting is delayed when the estimated exterior sky condition changes from a sunny sky state to an overcast sky state.