What is Luminous efficacy and Efficiency?

You may take it granted that these two words are the same in detail lighting feature. Yes ? Acturally they are different.
Luminous efficacy is a measure of how well a light source produces visible light. It is the ratio of luminous flux to power, measured in lumens per watt in SI. Depending on context, the power can be either the radiant flux of the source's output, or it can be the total power (electric power, chemical energy, or others) consumed by the source. Which sense of the term is intended must usually be inferred from the context, and is sometimes unclear. The former sense is sometimes called luminous efficacy of radiation, and the latter luminous efficacy of a source or overall luminous efficacy.
Not all wavelengths of light are equally visible, or equally effective at stimulating human vision, due to the spectral sensitivity of the human eye; radiation in the infrared and ultraviolet parts of the spectrum is useless for illumination. The luminous efficacy of a source is the product of how well it converts energy to electromagnetic radiation, and how well the emitted radiation is detected by the human eye.
The Differency
Luminous efficacy can be normalized by the maximum possible luminous efficacy to a dimensionless quantity called luminous efficiency. The distinction between efficacy and efficiency is not always carefully maintained in published sources, so it is not uncommon to see "efficiencies" expressed in lumens per watt, or "efficacies" expressed as a percentage.
Effficacy and DLC
DLC has released a series of verions to update standards of lighting. For example, to evalue if a lighting fixture comply with DLC 4.2 or not, one of the most important factor is the fixture’s efficacy, saying 125Lumen/watt, etc.
All the luminaries of CKRA’s Flood light, Wall pack Light, High bay, Area Shoe box light,etc are DLC V4.2 listed with proper efficacy.
Any requirement for high efficacy DLC listed products, please feel free to contact CKRA team.