Pre-Design

Exempt fixtures include emergency lighting, lighting within dwelling units, and lighting required by health and safety statutes. Certain display lighting is also exempt from the calculations.

In California you can use Title 24 instead of ASHRAE 90.1 as your standard for credit compliance and documentation.

Refer to the ASHRAE tables to figure out your lighting power allowances by building and space type (tables 9.5.1 for building type and 9.6.1 for space type). For each building or space type there is a corresponding LPD in the table.

LPD has no direct relationship with how much light the fixtures

Lighting power allowance, in watts, is the limit of total wattage for a building or space type allowed by ASHRAE 90.1-2007. It is derived by multiplying the LPD by the gross lighted floor area. 

Lighting power

For EAp2: Minimum Energy Performance, you have to hit a target of 10% lower LPD than the ASHRAE 90.1-2007 lighting allowance. For this credit, you can earn points starting at 15% reduction for one point, and in 5% increments up to 35% for 5 points (plus an Exemplary Performance point at 40%, via IDc1).  

The following are a few of the many factors to consider:

Hold an integrated design meeting with the entire design team, including the architect, structural engineer, civil engineer, landscaper, owner, and others to help determine what kind of roof is most feasible and desirable for your project building. 

This credit is fairly straightforward and simple to achieve by using light-colored roofing, a vegetated roof, or both, on a large area of the roof. (See the credit language for exact thresholds—which are higher for light-colored roofing than for vegetated roofs.)