Enhancing Comfort and Efficiency with Low-E Glass in Double Glazed Windows and Doors

A cool, metal oxide coating is applied to clear or tinted glass so that the appearance and performance are consistent regardless of glass thickness. Low-E glass, utilized in double glazed windows and double glazed doors, brings out the best in technology to enhance your views and comfort. Although Low-E glass typically costs about 15% more than ordinary glass, it reduces energy use by as much as 30-50%, by maximizing heat gain in winter while blocking harmful UV rays during summer. When used in insulated glass units, like upvc double glazed windows, the benefits are even greater. For hot climates, a low-E coating should be applied to the outside pane of glass. In contrast, for windows designed to retain heat in cold climates, the low-E coating should be on the inside pane of glass. Low-E glass is highly recommended by energy efficiency experts for its high performance and aesthetic appeal.

Window glass was revolutionized in the 1970s with the introduction of insulated glass (two or more pieces of glass with an air space between) and the debut of Low-E glass in 1979. The "E" stands for Emissivity, reflecting heat back to its source using an ultra-thin metallic coating. This coating allows visible light to pass while blocking significant amounts of UV and infrared (IR) light. UV light can damage skin, wood, fabrics, and colors, while IR light, which is essentially heat, can cause objects to become hot.

Low-E glass reflects this heat energy, helping to keep your home cooler in summer by preventing outdoor heat from entering. In winter, the heat from objects inside your home is reflected back indoors, enhancing comfort and efficiency. There are two types of Low-E glass: hard coat and soft coat. Hard coat Low-E glass is made by applying tin directly to molten glass, making it scratch-resistant. Soft coat Low-E glass involves applying a thin layer of silver in a vacuum, which is then sandwiched between two pieces of glass to protect it from oxidation and enhance insulation, often with argon gas.

Low-E glass also helps eliminate condensation on glass by keeping the inside surface temperature warmer. This is particularly beneficial in maintaining a comfortable indoor environment. For instance, on a cold night with an outside temperature of 0 degrees and a 15 mph wind, the inside temperature of a single pane window might be approximately 26 degrees, while regular double pane glass might register 35 degrees. In contrast, hard coat Low-E glass would be near 49 degrees, and soft coat Low-E glass at 62 degrees.

Some manufacturers have advanced Low-E glass technology by suspending thin, low-E transparent films between glass pieces, achieving excellent performance characteristics. These films can block up to 99.5% of UV light and provide insulation values twice that of soft coat Low-E glass. Given that homes can lose up to 40% of heating or cooling through windows, investing in high-quality Low-E glass is worthwhile.

Summer: Low-E glass in energy efficient windows filters long-wave radiation from the sun, reducing solar heat gain and helping keep your home cooler. It blocks unwanted ultraviolet radiation and reflects away long-wave infrared radiation, preventing excess heat buildup.

Winter: In winter, Low-E glass lets warm solar rays into your home while blocking internal heat from escaping. This reflective property helps conserve energy and reduce heating costs.

By incorporating Low-E glass in your double glazed windows and doors, particularly those manufactured in Sydney, you can significantly improve your home's energy efficiency and comfort, making it a smart investment for any homeowner.