What is the minimum percentage of efficient lightbulbs that must be installed to claim the...

The EDGE measure EEM22 - Efficient Lighting for Internal Areas focuses on reducing energy consumption through the use of efficient lighting. The EDGE User Guide specifies the requirements for this measure: "To claim EEM22 - Efficient Lighting for Internal Areas, at least 90% of the lamps in internal areas must be energy-efficient, such as LED or CFL, with a luminous efficacy of at least 80 lumens per watt. This threshold ensures significant energy savings while allowing for minimal exceptions in specific areas" (EDGE User Guide, Section 4.4: Lighting Efficiency Measures). Option C, 90%, directly matches this requirement. Option A (70%) and Option B (80%) are below the threshold, thus not qualifying for the measure. Option D (100%) exceeds the minimum requirement, but EDGE allows for flexibility with a 90% threshold to accommodate practical constraints: "A 90% requirement balances practicality with energy savings, recognizing that some areas may require specialized lighting" (EDGE Methodology Report Version 2.0, Section 5.4: Lighting Calculations). Therefore, the minimum percentage to claim EEM22 is 90% (Option C).