Unified Glare Rating (UGR): Why Is It So Important?

In response to the technology-driven world, optimal lighting in educational and working environments cannot be overlooked.


Glare can best be described as excessive brightness or discomfort caused by luminaires. Excessive glare holds the potential to disrupt concentration and strain the eyes, potentially amounting to welfare issues and an overall decline in productivity and well-being. To address the issue of glare, the concept of Unified Glare Rating (UGR) has emerged as a valuable metric in the field of commercial lighting design, and it is a crucial consideration when creating a lighting design for working environments.


In this blog, we’ll delve into what Unified Glare Rating is, the UGR range, its importance, the types of glare and how it can be reduced in different environments.


Please note, when selecting lighting solutions for educational and office environments, it’s essential to consider all factors beyond glare, including performance, lighting level, comfort, colour rendering, uniformity, direction, colour, shadow and ambience.



What is Unified Glare Rating (UGR)?

Unified Glare Rating, typically referred to as UGR, measures the intensity of glare produced from a luminaire within a given space. While there are recommended universal UGR guidelines from specialists, there are no legal requirements.


The level of UGR ranges from 40 (high glare) to 5 (low glare). The lower the UGR, the better. A recommended UGR range typically falls between 16 and 19 for office and educational settings. However, this range should be approached as a guideline rather than an absolute rule.


It’s important to recognise that the optimal UGR can vary depending on influencing factors specific to each environment, and therefore, UGR should be used intelligently with an understanding of the unique characteristics of each surrounding.


Educational spaces may have distinct UGR requirements, considering the diverse activities carried out within classrooms and lecture theatres. But in comparison, specific environments, such as offices and retail spaces, may require unique UGR considerations to cater to particular tasks and user needs.


UGR glare can be evaluated using two distinct avenues: glare tables or lighting design software. While glare tables provide an elementary grasp, lighting design software offers a more accurate calculation and meticulously calculates optimal luminaire placement based on the purpose and occupancy of the space in real life. At Mount Lighting, our professionals use advanced lighting design software to ensure accuracy across all our evaluations.


Why is UGR important?

There are several reasons why UGR is considered important and crucial to consider during the lighting design stage, including:

Human Well-being and Comfort

Suitable UGR helps ensure that an educational environment is comfortable and visually pleasing for students to learn in. Keeping glare to a minimum helps to prohibit discomfort, eyestrain, headaches and more, ensuring comfort for light recipients.

Productivity and Performance

Reducing glare and ensuring appropriate UGR levels can increase concentration levels, reduce fatigue, and increase overall productivity and performance.

User Satisfaction

Providing a working environment that is designed to meet fundamental needs helps to contribute to occupant satisfaction and well-being.


What Types Of Glare Are There?

There are two types of glare: directed and reflected. Each of these types of glare can impact the user differently.

  • Direct glare is where the occupant looks directly into the light source, whereas
  • Reflected glare occurs when light rays bounce off a glossy or reflective surface. This surface can be either vertical (screens, etc.), or horizontal (desk surfaces, for example).

We also refer to glare in different levels of seriousness, “Disability”, and “Discomfort”.

  • Discomfort glare may not impair vision but, instead, will cause discomfort through visual strain or irritation due to a noticeable difference in brightness levels.
  • In comparison, disability glare is where the light source significantly reduces visibility and prevents the occupant from being able to see clearly.


How Can Glare Be Reduced?

There are, however, ways to reduce glare from luminaires, including:



Beam Angle

Lighting beams play a significant role in reducing glare. By carefully controlling the direction and intensity of a luminaire’s beam, you can direct light where it’s needed without causing discomfort to the user.

Surface Reflectivity

The interaction between light and surfaces can sometimes lead to unwanted reflected glare. This occurs when light bounces off surfaces. However, it’s possible to effectively minimise glare by ensuring surface uniformity and consistent luminance while maintaining the same lumen output.


Luminaires that are visible to the eye can amount to glare and cause discomfort. Shading and shielding light sources prevent the harsh, blinding sensation that often accompanies glare.


Putting systems in place like Casambi can assist with choosing appropriate output and contribute towards reducing the amount of glare.


Intelligent lighting controls like Casambi are integral in enhancing the human-centric aspect of lighting, providing automatic control over lighting levels. Designed to interact with natural light that comes through windows harmoniously, Casambi delivers additional light where needed, all while skilfully maintaining suitable UGR levels.

Luminaire Placement

Placement of a luminaire is often an effective technique to minimise glare. Each space will have an appropriate height and angle for where luminaires should sit, which can help prevent light from directly hitting the line of sight. In particular environments, such as classroom reading areas and workspaces, this is especially important.

Ambient Light

Incorporating natural or diffused light sources with artificial lighting can reduce light and shadow contrast, lessening glare and supporting a more comfortable and harmonious atmosphere.


Experience Enhanced Comfort With UGR Compliant Lighting Solutions

Our specialists at Mount Lighting understand the implications glare can impose, especially on the educational sector. With our UGR19-supportive products, light the way to a glare-free school environment. Contact our lighting design specialists for a brighter, more comfortable learning space.


Mount Lighting produce a wide range of low-glare lighting products including:

  • Lens-Line – Surface or suspended Linear LED
  • Blade – Suspended direct/indirect LED panel
  • LEP32LG600– recessed LED panel 
  • Sonic – recessed downlight
  • Enforce – surface or suspended downlight


The Lens-Line linear LED range is incredibly energy efficient and holds the Made in Britain mark as it is manufactured in Britain by Mount Lighting. 


If you want to learn more about Unified Glare ratings or want to explore our range of UGR lights, please don’t hesitate to get in touch with our team now by calling 01582 369 005, live chat function, or email [email protected]

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