It is a psychological parameter that measures the subjective reaction of the light emitted by the lighting device in the indoor visual environment to the human eye, and its value can be calculated by the CIE unified glare value formula according to the specified calculation conditions.
The original industrial and civil lighting design standards stipulate that the direct glare of indoor general lighting is limited according to the brightness limit curve. This limitation method is only for the glare of a single lamp, and cannot represent the total glare effect produced by all lamps in the room. Therefore, CIE put forward the calculation formula of unified glare value (UGR) on the basis of synthesizing the calculation formulas of glare in various countries. It is suitable for the general lighting design of a simple cube-shaped room. The lamps are evenly arranged at equal intervals, and the lamps are double-symmetrical with light distribution.
The UGR of LED downlights is divided as follows:
| Value | Feeling |
| 25-28 | Intolerable |
| 22-25 | Uncomfortable |
| 19-22 | Tolerable level of glare |
| 16-19 | An acceptable level of glare, such as offices and classrooms that require light for a long time, is suitable for this level. |
| 13-16 | Does not feel dazzling |
| 10-13 | Can’t feel the glare |
| ＜10 | Professional grade products for hospital operating rooms |
Of course, UGR is not a single product value, it is also related to the use environment of led downlights.
For example, the lower the reflectivity of the room, the higher the UGR. The principle is very simple: the greater the contrast between the ambient light and the light of the lamps, the greater the eye discomfort. This is why environments with low reflectivity, such as bars or KTVs, generally use led downlights and spotlights instead of hanging a large lamp inside.
At this time, the problem comes. As a lighting company, you don’t know what environment your customers put the lights in, so what should you do? Since it is impossible to control the environment, then we make the UGR of the product itself below 19/16/13/10, so that it will not cause damage to the eyes of customers.
So as an ordinary consumer how to choose suitable led downlights? It’s also very simple, you can choose downlights ugr 19 with micro-structured anti-glare film prism sheet.
Why UGR19? Because UGR has a characteristic, that is, it is easy to reduce from 25 to 19, but it is very difficult to reduce from 19 to 10. Assuming you only spend twice as much power from 25 to 19, going from 19 to 16 may cost 5 times as much, and the price will be very expensive. This is why I recommend UGR19 as a relatively cost-effective choice.
Post time: Jul-25-2022