Understanding Low E Coatings
Insights into the complexities of Low E coating and their importance in making informed choices.
Understanding Low E coatings
In the ever evolving field of architecture, material choice plays a crucial role in both the performance and aesthetics of a building. Glass is at the forefront of this evolution - and Low Emissivity (Low E) coated glass has become a key innovation for achieving energy efficiency and aesthetic versatility.
At Metro Glass, we’re proud to be New Zealand’s local experts in glass performance and technology. Our team helps architects, builders and homeowners understand the science behind Low E coatings. By combining technical expertise with practical insights, we help our clients make informed decisions that enhance both living comfort and design aesthetics.
The science behind Low E coatings
Low E coatings are designed to improve the thermal performance of glass. The most common process involves offline coating, where sputtering technology bombards a target material with electrons, depositing a thin layer onto the glass surface. This layer is composed of various metals, oxides, and nitrides, each chosen for specific properties that influence the final product's performance and appearance. These soft-coat Low E products differ from online coated products applied to molten glass. Online coatings create a finished product that is more stable and weather-resistant enabling the use of single glass rather than necessitating insulated glass, however, they tend to have a hazy appearance and “medium” performance.
Offline (sputter) coatings are created using patented recipes unique to each glass manufacturer. The combination of different materials results in a variety of Low E products, each with distinct characteristics. For instance, the stack of layers determines the glass' colour, thermal efficiency, solar control, and clarity. This diversity allows architects to select glass that not only meets performance standards but also aligns with their design vision.
Performance and aesthetic consistency
Achieving both high performance and visual consistency is one of the key challenges when working with Low-E coated glass. Different glass types - such as toughened or annealed - can present subtle variations in appearance. Ensuring these align seamlessly requires precise control over the coating process and an expert understanding of glass behaviour.
At Metro Glass, we take this precision seriously. Under the guidance of Rahul Jain, our highly qualified glass engineer with extensive international experience in sputter coated glass manufacturing, ensures that our Low E products deliver consistent aesthetics and outstanding performance. Rahul’s depth of knowledge and global insight play a pivotal role in the ongoing development of the Metro Glass range, reinforcing our commitment to quality, innovation and technical excellence.
Practical considerations for architects
For architects, choosing the right Low E coated glass involves balancing performance requirements with aesthetic goals. Low E coatings enhance the thermal performance of windows by reflecting infrared energy while allowing visible light to pass through. Sputter-coatings can also be designed variably for how much short-wave energy these transmit (the part of the solar radiation from the sun that influences direct heat into the home/building and hence the potential for overheating). Variability in performance against short-wave energy directly impacts solar control functionality (Solar Factor) — hence a range of performance and glass options from this perspective alone. The capabilities of sputter-coated glass in terms of achieving different combinations of thermal efficiency (glass U-Value) and solar control (Solar Factor) results in a range of options for improving energy efficiency from the perspective of both heating and cooling costs for buildings.
The method of applying individual layers of sputter coatings can vary, as can the material deposited per layer. Different materials and application techniques can help achieve similar performance but may result in varying aesthetics. For instance, each material used in the coating has a characteristic colour, which can influence the final appearance of the glass. This makes it crucial for architects to collaborate closely with suppliers like Metro Glass to ensure the selected product meets their design and functional specifications.
Some Low E products also feature a protective coating, which is beneficial for handling up until tempering (toughening), which enhances efficiencies in the factory and in turn timely supplies. This protective layer also serves to reduce the risk of fingerprints and accidental marks during insulated glass manufacturing, ensuring the glass maintains its pristine condition from the factory to the final installation.
Our glass expertise
As all flat glass sheets for building materials in New Zealand are imported, the role of a knowledgeable local supplier becomes even more critical. Metro Glass stands out as a leader in the industry, offering architects in New Zealand unparalleled expertise and a comprehensive range of Low E coated glass products.
With a focus on quality, innovation, and customer satisfaction, Metro Glass helps architects navigate the complexities of Low E coatings. By understanding the science and nuances of these coatings, architects can enhance their designs with glass that offers superior performance and aesthetic appeal. Partnerships with knowledgeable, experienced, and supportive suppliers, empower architects to create energy efficient, visually stunning buildings that stand the test of time.