EPAct 2005/ASHRAE 90.1
To promote the use of energy-efficient lighting in commercial and industrial buildings, ASHRAE 90.1 requires manual or automatic controls or switches that allow occupants to dim lights and turn them on or off. The Energy Policy Act of 2005 (EPAct 2005) allows building owner to deduct the entire cost of an interior lighting upgrade subject to a maximum of $0.60 per sq.ft. if bi-level switching is installed, lighting controls meet ASHRAE 90.1-2001, and lighting power density is reduced by at least 25% to 40% of levels prescribed by ASHRAE 90.1-2001.