You are now visiting our Global professional lighting website, visit your local website by going to the USA website


What are “cold” and “hot” lumens?


These terms do not have any photometric or engineering meaning. However, cold lumen is the light output of the LED chip alone when it is first switched on. Hot lumens, refers to the light output of the LED when it is fully warmed up in the luminaire. The hot lumen value may be 30% - 50% lower than the cold value.




HEN on the Road One Day Technical Conference

11.05.2017, Surrey


Smart to Future Cities 

16.05.2017, London


Smart Buildings 

23.05.2017, London


View all events