What are the Interim Lighting Rules?

From January 1, 2006 until the Treasury Department issues final regulations, the Commercial Buildings Deduction’s Interim Rules for Lighting Systems are in effect.

The Interim Rules offer an accelerated tax deduction equal to the complete cost of installing energy-efficient interior lighting, capped at $0.30-$0.60/sq.ft. proportional to lighting power density (LPD, calculated as watts per square foot) savings of 25-40% below the LPD values prescribed in Standard 90.1-2001.

Under Commercial Building Deduction rules, “energy-efficient interior lighting” is defined as:

1) lighting that is classified as interior lighting;

2) otherwise depreciable as a cost;

3) installed in the United States;

4) part of new construction or renovation within the scope of the ASHRAE/IES 90.1-2001 Standard, including retrofits; and

5) certified to reduce LPD to 25-40% less than the minimum requirements in Standard 90.1-2001’s Table 9.3.1.1 (building area method) or Table 9.3.1.2 space-by-space method) (not including additional interior lighting power allowances).

Warehouses are an exception; in this case, 90.1 must be exceeded by 50% to qualify for a tax deduction of $0.60/sq.ft.

In addition, 1) all controls provisions in Standard 90.1-2001 must be met, 2) bi-level switching must be installed in all occupancies except hotel and motel guest rooms, store rooms, restrooms and public lobbies, and 3) the minimum requirements for calculated light levels as established in 9th Edition of the IES Lighting Handbook must be met.

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