How do daylight and artificial lighting interact to influence LEED EA credits?

• A. Daylight reduces artificial lighting needs, lowering energy use.
• B. Daylight increases cooling loads and reduces IEQ.
• C. Artificial lighting never affects energy use.
• D. Daylight only affects aesthetics, not energy.

Answer: (A)

Daylight harvesting lowers the energy needed for electric lighting, which is a primary way LEED EA credits are earned. When daylight provides enough illumination, lighting controls dim or turn off electric fixtures, reducing lighting power and overall building energy use. That reduction in lighting energy is a core path to improving a project’s energy performance for LEED credits. At the same time, daylight brings solar gains that can raise cooling loads, so the design should use shading, glazing, and envelope strategies to manage those gains and keep the net energy savings positive. The other statements aren’t accurate: daylighting isn’t just aesthetics, and artificial lighting clearly affects energy use; daylighting can also support better indoor environmental quality when it provides comfortable, well-lit spaces.