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Home / News / Industry News / What types of Low-E coatings are available for energy saving insulated glass, and how do they differ?
Low-E coatings, which are essential for increasing the energy saving insulated glass, come in two main variations: hard coats (pyrolytic) and soft coats (sputter). Each type serves a different purpose and exhibits differences in durability, use, and performance.
Hard coat (pyrolytic) Low-E coating:
A hard coat Low-E coating is applied during the glass manufacturing process to increase durability and make it suitable for exterior applications. Typically, a metal oxide, such as tin oxide, is melted onto the glass surface while it is still in a molten state. This process creates a durable coating on the glass itself.
Hardcoat coatings are robust and can withstand exposure to external elements, making them suitable for the exterior surfaces of single-pane windows and insulated glass units (IGUs). Their robustness ensures a long service life and minimizes the risk of damage during handling and installation.
Hard-coat Low-E coatings are more durable, but tend to have slightly lower emissivity levels compared to soft-coat alternatives. This difference affects its performance characteristics, especially in terms of infrared reflection and heat transfer control.
Soft coat (sputter) Low-E coating:
In contrast, Soft Coat Low-E coatings are applied in a vacuum chamber after the glass is formed. This method allows for a more delicate application of the metal layer, often composed of silver or other precious metals, resulting in improved reflectance to infrared radiation.
Soft coat coatings are typically used on the inner surface of the outer glass of double-glazed or triple-glazed IGUs. Although they offer excellent thermal performance, their delicacy often requires protection in the form of additional layers or laminated glass structures.
The advantage of Softcoat Low-E coatings is that they provide superior emissivity control, allowing for higher levels of reflectivity for infrared radiation. This property makes it very effective in both winter and summer, minimizing heat loss in the cold season and reducing heat gain in the warm season.
