Glare control strategy UGR < 19 or UGR =< 19?

Yara Ibrahim

ABT bv.

LEEDuser Basic Member

0 thumbs up

January 21, 2026

The EQ Credit Interior Lighting specifies for the ‘Glare Control’ strategy to “achieve a Unified Glare Rating (UGR) rating of <19 using software modelling calculations of the designed lighting”.
Would lighting fixtures with UGR = 19 be acceptable? Or is the <19 a strict lower than 19 cut-off?

Discussions with manufacturers have raised that an industry standard is UGR = 19. And, in the new LEED V5, the glare control requirement is clearly defined as UGR =<19.
So, is it possible that what is meant in the LEED v4.1 version is the same? Anyone has any insight on that?

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Denise Bevilaqua

HIGHLAND ASSOCIATES

LEEDuser Basic Member

30 thumbs up

Wed, 01/21/2026 - 13:28

Yara, Hi.I believe the intent of this requirement in both v4.1 and v5 is to understand the UGR of the specific lighting conditions in your space. I don't believe it is appropriate to cite a UGR value from a fixture cutsheet. As you noted, credit language states that a UGR of <19 needs to be demonstrated "using software modelling calculations of the designed lighting”. This means that you need to model the space with the lighting as designed for your project including the room geometry, surface reflectance(s), and observer points. v5 Guidelines added an option to use the UGR "Tabular method", but my understanding is that this method still requires that you adjust the luminaire's "pre-calculated" table for your project conditions.