Does UV Impact Matter for Low-E Glass Selection?

Whether the UV impact of Low-E glass requires prioritized attention primarily depends on the building’s functional positioning and the actual needs of indoor occupants and various facilities. Specifically, neither Low-E glass nor clear glass allows beneficial medium-wave ultraviolet (UVB) to penetrate indoors, resulting in minimal differences in their impacts on human health in this regard. However, Low-E glass outperforms Standard（Clear）Glass glass and Ultra-Clear Glass in UV attenuation efficiency, making it the optimal choice for preventing skin damage caused by UV radiation. Additionally, UV radiation significantly affects the durability and aesthetics of bamboo/wood materials and polymer materials. Therefore, the need to prioritize this performance should be determined based on specific application scenarios.

1.  Impact on Human Health: Prioritize Skin Protection

UV radiation exerts a dual effect on the human body: moderate exposure is beneficial, while excessive exposure is harmful. On one hand, moderate UVB promotes vitamin D synthesis, which is beneficial for bone health. On the other hand, excessive UV exposure can damage the eyes and skin, impair the immune system, and cause issues such as sunburn and decreased vision.

UV radiation can cause certain harm to the eyes, skin, and other human organs, with UVA and UVB being the main components responsible for skin damage. According to actual measurement data from the previous article, the UV attenuation capacity of various glass types ranks as follows: Low-E Insulating Glass > Clear Insulating Glass > Ultra-Clear Insulating Glass. Compared to the latter two, Low-E insulating glass attenuates UV radiation more efficiently and reduces indoor UV incidence. Thus, if concerned about UV-induced skin damage, installing Low-E insulating glass is the optimal choice.

From the perspective of glass transmission characteristics, however, neither Low-E glass nor single-pane clear glass can provide beneficial UV radiation indoors—UV rays transmitted through these two types of glass are almost entirely long-wave ultraviolet (UVA), while UVB is completely blocked. In fact, except for insulating glass made with ultra-clear glass without Low-E coating, no other glass allows UVB to enter indoor spaces. Even sunathing by the window is far less effective in obtaining beneficial UV exposure than being outdoors. Currently, the scientific community has not found direct benefits of UVA to the human body. Therefore, humans cannot gain any health benefits from UV radiation transmitted through glass, and the difference between Low-E glass and single-pane clear glass in this regard has minimal impact on human health.

Many people worry that "insufficient UV radiation will affect sterilization and disinfection." However, sterilization and disinfection primarily rely on short-wave ultraviolet (UVC), which cannot penetrate the Earth’s atmosphere to reach the surface. Although the short-wave portion of UVB has certain bactericidal capabilities, it is blocked by most types of glass (except ultra-clear insulating glass). Therefore, UV radiation transmitted through glass inherently lacks sterilization and disinfection effects, which is unrelated to the attenuation performance of Low-E glass.

2.  Impact on Bamboo and Wood Materials: Recommend Prioritizing UV Attenuation

For residential buildings with extensive use of bamboo and wood materials, it is necessary to prioritize the UV attenuation performance of Low-E glass when selecting it, to minimize indoor UV exposure.

Bamboo and wood materials and their products are common basic materials in indoor settings, widely used in decoration, furniture manufacturing, flooring, and as core raw materials for paper products such as books and paintings. Their main components (e.g., cellulose, hemicellulose) have a certain ability to absorb UV radiation. After absorbing UV rays, the molecular structure of these materials is damaged to varying degrees, leading to deterioration of their physicochemical properties. This ultimately affects the stability, durability, and aesthetics of bamboo and wood materials, resulting in issues such as fading, cracking, and brittleness. Low-E glass can effectively attenuate UV radiation, significantly delaying this damage process, so it should be given priority in such scenarios.

For example, museums and libraries must consider the UV attenuation of Low-E glass to reduce UV impact on cultural relics, books, and paintings. 'GB/T 23863-2024 Specification for Lighting Design of Museums' stipulates that the relative content of UV radiation in light should be less than 20μW/lm. 'JGJ38-2015 Code for Design of Library Buildings' requires measures to eliminate or mitigate UV damage to library materials.

3.  Impact on Polymer Materials: Recommend Prioritizing UV Attenuation

To reduce UV damage to indoor polymer materials, the UV attenuation performance of Low-E glass should be emphasized when selecting it.

Polymer materials, including plastics, rubber, fibers, films, adhesives, and coatings, are widely used in indoor furniture and decorative installations. When these materials are exposed to UV radiation for a long time, their molecular chains undergo scission, leading to decreased physicomechanical properties and changes in chemical structure. This ultimately results in partial or complete loss of usability, manifested as "photoaging" phenomena such as hardening, stickiness, brittleness, discoloration, and reduced strength. The efficient UV attenuation capability of Low-E glass can effectively delay the photoaging process of polymer materials and extend their service life, so it should be prioritized in relevant scenarios.

Previous Article: How Much UV Radiation Can Low-E Glass Attenuate？

References: 

https://www.sciencedirect.com/science/article/pii/S0160412024001211

https://std.samr.gov.cn/gb/search/gbDetailed?id=208E903AB68979F3E06397BE0A0AB2B9

https://www.zslib.com.cn/jingtaiyemian/zwgk/AttachDownLoad.pdf