Efficacy, definition of

The amount of energy service or useful energy delivered per unit of energy input. Often used in reference to lighting systems, where the visible light output of a luminary is relative to power input; expressed in lumens per Watt; the higher the efficacy value, the higher the energy efficiency.

• New Square LED's more light directional
  A new LED fabrication technique produces squares of LED's that are more directional.

• Appraising Marvel et al.: Implications of forcing efficacies for climate sensitivity estimates
  A guest article by Nicholas Lewis Note: This is a long article: a summary is available here. Introduction In a recent paper[1], NASA scientists led by Kate Marvel and Gavin Schmidt derive the global mean surface temperature (GMST) response of the GISS-E2-R...
• Universal Display Unveils the Most Efficient OLED Kitchen Lights Ever Produced
  The team at Universal Display Corporation recently unveiled prototypes of a sleek, modular OLED kitchen light that blows away a set of environmental specifications proposed in a challenge funded in part by the US Department of Energy...