We in Connecticut will adopt the 2003 IEC in September. In addition to the 50% light reduction controls mentioned, we will be limited to Table 805.5.2, "Interior Lighting Power". This will limit the overall lighting wattage of various buildings to levels below that of the NEC's Table 220.3(A).
For example, under the NEC, we are to allow 2 VA/sq. ft., but the IECC wants a cap of 1.2 watts / sq. ft.; hotels from 2 down to 1 overall or 1.3 for a tenant space; schools from 3 down to 1.2; offices from 3.5 down to 1 overall or 1.1 for tenant space.
Of course, the NEC includes receptacles in some of these "General Lighting Loads", and the IECC is for only lighting fixtures.
I find it interesting that some occupancies allow more wattage than in the NEC. i.e. Churches in the NEC allow 1 VA/ sq. ft. , but, the IECC limits wattage to 1.3 overall and 2.4 for tenant spaces. All in the name of saving energy. It is just a little like comparing apples to oranges.
