UGR And Glare Control In Recessed LED Downlights

What UGR Measures

Unified Glare Rating describes how much discomfort a lit installation causes people looking through the space. Lower is better. Most office and hospitality specifications ask for UGR below 19, and corridors where people walk toward the fitting are where a failure is most obvious.

What Actually Produces A Low Figure

Three things: recessing the light source deep enough that it leaves the normal viewing cone, shielding it behind a reflector or a dark baffle, and avoiding a bright diffuser face flush with the ceiling. A fitting can hit UGR below 19 with a modest chip and lose it entirely by mounting the same chip flush.

Where It Matters Most

Hotel corridors, aisles and lobbies, because people walk along the axis of the fittings and look ahead rather than down. Meeting rooms, because attention is directed horizontally. Open-plan offices with screens, where reflected glare compounds direct glare.

Reflector Colour Changes The Result

A dark reflector absorbs more of the light that would otherwise leave the aperture at a shallow angle, which lowers apparent brightness at the aperture. A silver or white reflector returns more of that light into the room, which raises efficiency and raises glare. Choose from the room, not from the catalogue photo.

Do Not Solve Glare By Reducing Output

Dimming a badly shielded fitting lowers the lux level without fixing the source brightness ratio that causes the complaint. Specify a low-glare fitting and then set the level, rather than the other way round.