Unified Glare Rating | Technical Guide

Technical Guide Unified Glare Rating (UGR)

Lighting Guide | Unified Glare Rating (UGR)

What is UGR (Unified Glare Rating)?

UGR is a measure of glare from luminaires, light through windows and light sources. In simpler terms, UGR tells us how likely a luminaire in our field of vision is to cause discomfort or interference with our ability to see.

UGR helps you figure out how bright or glaring a light feels to your eyes. Imagine sitting in a room and feeling like the light is too sharp, or it's making you squint a lot—that's what UGR measures.

Choosing the right UGR value

UGR is all about comfort for your eyes. When choosing lights, a lower UGR ensures you get a bright room without the discomfort of overly sharp or glaring lights. It means you're less likely to get eye fatigue or be disturbed by excessive brightness.

For workspaces, especially where computers are used, you'd typically want a light that has a UGR value of 19 or less. The best lights for comfort can even go down to UGR 6, which means they're super gentle on your eyes.

In homes, particularly for spaces where you read, watch TV, or use a computer, choosing lights with a low UGR can reduce eye strain, prevent screen glares, and improve the overall visual experience. And a low UGR value at the dining area prevents harsh glare, allowing individuals to see their food clearly and enjoy conversations without squinting or straining their eyes.

UGR in practice

When choosing a luminaire with reduced glare or a low UGR, several design features can make a difference. Luminaires with honeycomb louvers mitigate glare by obstructing direct viewing of the light source. Additionally, fixtures that position the bulb recessed or deeper inside can prevent direct light from being overpowering.

Precision-designed reflectors ensure that light disperses uniformly. Meanwhile, diffusers, often made of matte glass or plastics, play a pivotal role in softening light output. Think of luminaires designed like globes, with internal bulbs, who offer a diffused glow, providing ambient, less harsh lighting.

Lastly, indirect lighting is an effective glare-minimization strategy. Uplight luminaires cast light upwards, reflecting off ceilings or walls, creating an even and glare-free ambiance.