Q: What's the difference between luminaire luminous flux and total luminous flux

A: Total luminous flux refers to the luminous flux emitted by a light source in all directions. It is essentially the theoretical peak value of the LED chip itself.

Luminaire luminous flux, on the other hand, is the value calculated after accounting for all factors such as power drive conversion efficiency losses, consumption due to light distribution design for beam shaping, and losses from lens transmittance materials. In other words, it represents the actual luminous flux of the lighting fixture.

Depending on the design of the floodlight, the luminaire luminous flux can sometimes reach up to 85% of the total luminous flux, but it may also fall below 50%.

If the floodlight is turned on in a cooled state, the measured luminaire luminous flux will be higher.

Therefore, to obtain an accurate luminaire luminous flux measurement, the floodlight should be operated for more than 30 minutes until it stabilizes before taking measurements.