Lumen is the standard unit for measuring the amount of led high bay lights produced by a light source. It is equal to the amount of light hitting one square foot of surface one foot away from the light. Essentially, the higher the lumens, the brighter the light.
Energy saving lighting is about reducing the wattage used in a light fitting while maintaining similar light output.
Lumens per watt
This truly shows the efficiency of the LED high bay lgihts product. For example a 200lm product consuming 3 watts of electricity = 66 lumens per watt. Lumens per watt vary from product to product depending on the LED chip used, how hard the product is being run, and the construction of the fitting and how effective the heat sink is at removing the heat.
The beam angle is something you need to pay attention to when choosing the right LED high bay lighting for the space. This is as important as the Lumens. Beam angle indicates the spread of light from the light source. A narrow beam gives a concentrated light which is better for accent lighting. A wide beam gives a more general, softer light.