When replacing one light source with another, you need a medium of exchange, and lumens exist to serve as that medium. However, LEDs may be the end for the old faithful lumen. In practice we’ve found it to be a significantly inaccurate indicator of brightness where LEDs are concerned.
On the “rebound effect” in energy efficient lighting or why LEDs aren't like other energy efficiency
The brightness you see versus the brightness you read about: on light levels, LEDs, and the shortcomings of the lumen
The industry uses a measure called the "lumen" to measure light volume across light sources. Based on our installations, we believe the better quality the light, the "brighter" a lumen appears. Here we'll explore why we think the lumen fails to indicate brightness properly where LEDs are concerned and what we do about it.