It’s so easy to replace 400W metal halide high bay by 100W LED.
First we look at the parameters of the two lamps.
Luminous flux (Luminaire): 17359lm
Luminous flux (Luminaire): 19540 lm
Luminous flux (Lamps): 32000 lm
Luminaire Wattage: 372.0 W
Next we use Dialux to do a simulation analysis.
The simulation of 100 watt LED round high bay
We can see that the illuminance of the two lamps is very close by simulation. That is why 100 watt LED round high bay is a replacement for 400W metal halide high bay.