This credit has two compliance options, which means your team has some flexibility in how it chooses to demonstrate compliance.

Option 1 deals directly with your exterior fixtures (both luminaires and illuminated signage) and the lamps you use. Option 2 assesses your building’s contribution to light pollution through nighttime illumination measurements taken around the project boundary.

If some of your exterior fixtures can’t comply with Option 1, there’s still a chance that your building can comply with Option 2. Unfortunately, there’s no good way to know whether you’ll comply with Option 2 except to perform the actual measurements, so teams often try to comply with Option 1 first.

This credit is easier to earn compared to LEED 2009, as the interior lighting component has been removed entirely. Teams now need to be concerned with lights on the building exterior only.

What’s New in LEED v4

• The interior lighting requirements have been removed from this credit.
• Projects can no longer demonstrate compliance with the exterior lighting requirement by meeting maximum footcandle levels (per IESNA RP-33). (The option to show a difference in illumination levels of no more than 20% between lights-on and light-off levels, at each measurement point, is still available.)

Readiness Review Questions

• Are exterior fixtures shielded? Can you determine the lumen value of currently installed lamps to confirm if fixtures exceed 2,500 lumens?

• Are there opportunities to reduce exterior lighting levels? Can unnecessary fixtures be removed or de-lamped?

• Is light trespass at the LEED project boundary minimal, likely qualifying the project for Option 2?