Dear LightingTaxDeduction.org,

Can lighting controls such as dimming and occupancy sensors contribute to the lighting power density savings needed to qualify for the CBTD under the Interim Lighting Rule?

Answer: Dimming strategies such as load shedding, daylight harvesting or adaptive compensation are not recognized as methods to reduce lighting power density using the conventional methods specified in ASHRAE/IESNA 90.1-2001, but can be using the energy cost budget method, which requires computer modeling. In addition, dimming would be considered as satisfactory for the bi-level switching requirement.

Regarding occupancy sensors, the answer is no, they do not count towards reducing lighting power density, but it is possible that they may be accepted as a component of the bi-level system. Here is a possible scenario. Every other fixture is controlled by an occupancy sensor so that they are only ON when the space is occupied. This would not be acceptable if the state or local code has specific definitions for bi-level switching that do not include this option or if the certifier would not accept this as bi-level switching, however.

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