Outdoor Lighting: Understanding BUG Ratings (video)

BUG (Backlight, Uplight, Glare) ratings make it easier to find the right outdoor lighting for your facility, but only if you understand what they mean.

For reference, any light that comes off the fixture below 60 degrees is considered the ideal usable light. In theory, you’d prefer that all of your light goes there.

BUG ratings measure the backlight, uplight and glare of a fixture. If properly used, they can help you put the most light in the places you need it and avoid any light creep that could violate local ordinances.

Here’s a quick look at where the light is coming from:

  • Backlight is any light coming from the fixture between the 60- and 90-degree point. Backlight that leads to light trespass is bad, but sometimes backlight can be okay.
  • Uplight is any light that is sent up into the air. It’s mostly just light pollution that causes sky glow.
  • Glare is light coming out of the 60- to 90-degree range from the front of the fixture. That’s basically the angle that blinds you rather than helps you see.

Backlight, uplight and glare are each scored on a scale of 0 to 5, with 0 being the lowest lumen or light output.

BUG ratings are useful tools that can help you design an evenly lit outdoor space that promotes safety and security without bothering your neighbors.