Low-E Glass (Low-emissivity)
Read about what is low-e glass and the benefits when used in a window.
What is Low-E Glass?
Low-Emissivity (Low-E) glass, a revolutionary product offered by Safe and Sound Windows, is designed to enhance the energy efficiency of windows and doors across various climates.
This specialized glass features a microscopically thin coating, thinner than a human hair, which plays a crucial role in controlling the energy flow through windows.
The essence of Low-E glass lies in its ability to minimize the passage of ultraviolet (UV) and infrared (IR) light, while allowing an optimal amount of visible light to penetrate, thereby improving lighting and reducing heating and cooling costs significantly.
Role of Low-E Coatings
Low-E glass utilizes transparent coatings to reflect long-wave infrared energy (heat) while allowing visible light to pass through. These coatings are instrumental in reducing radiant heat loss through the glass in colder months by reflecting interior heat back inside. Conversely, during warmer months, they help keep interiors cool by reflecting outdoor heat away from the building.
Role of Low-E Coatings
Safe and Sound Windows provides two primary types of Low-E coatings, catering to different climate needs:
- Passive Low-E Coatings: Aimed at maximizing solar heat gain, these coatings help in passive heating of homes or buildings, reducing the need for artificial heating.
- Solar Control Low-E Coatings: These coatings are designed to limit solar heat gain, aiding in keeping buildings cooler and minimizing air conditioning costs.
Types of Low-E Coatings
Safe and Sound Windows offers two primary types of Low-E coatings, each designed to meet specific climate needs and enhance the energy efficiency of windows and doors. These coatings are composed of micro-thin layers of metals such as tin, silver, and zinc, sometimes in combination, to optimize their performance.
Passive Low-E Coatings
Passive Low-E coatings are engineered to maximize solar heat gain within a building, creating a “passive” heating effect. This is particularly beneficial in colder climates where the goal is to reduce reliance on artificial heating systems. By allowing more solar heat to pass into the home, Passive Low-E coatings can significantly lower heating costs. The placement of these coatings is strategic; they function best when applied to the third or fourth surface of the glass, furthest away from the sun. This positioning helps in retaining interior warmth by reflecting long-wave infrared radiation back into the home.
Solar Control Low-E Coatings
In contrast, Solar Control Low-E coatings are designed to limit solar heat gain, making them suitable for warmer climates or buildings that receive significant direct sunlight. These coatings help maintain cooler interior temperatures by reflecting short-wave infrared and unwanted solar heat away from the building. As a result, they can considerably reduce the energy consumed by air conditioning systems. Solar Control Low-E coatings demonstrate optimal performance when applied to the second surface of the glass, closest to the sun, effectively blocking heat before it enters the building.
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What are the Benefits Of Low-E Glass?
Improved Insulation
Low-E glass, developed by Safe and Sound Windows, significantly enhances the insulation of windows by utilizing a microscopically thin, transparent coating that reflects long-wave infrared energy, or heat. This innovative technology reduces the emissivity of window glass surfaces, improving a window’s insulating properties.
This remarkable reduction in emissivity means that during winter, when interior heat attempts to escape to the colder outside, the low-E coating reflects the heat back inside, minimizing radiant heat loss through the glass. Conversely, in the summer, the coating reflects outdoor heat away, maintaining cooler interior temperatures.
Energy Efficiency
The primary purpose of low-E glass is to control and minimize infrared light, which translates to heat, thereby reflecting heat back into the home during winter and keeping solar heat gain at bay during summer. This dual action contributes significantly to a building’s energy efficiency. By blocking up to 96 percent of infrared light from the sun, cooling bills can see a dramatic decrease in the summer months.
Additionally, the reflection of infrared light back into the home acts as an extra layer of insulation, keeping windows warm and further saving on heating costs in the winter. This improvement in energy efficiency not only leads to reduced heating and cooling costs but also contributes to a more comfortable living environment throughout the year.
UV Protection
One of the standout benefits of low-E glass is its ability to significantly reduce the amount of ultraviolet (UV) radiation that enters a building, thereby protecting interior furnishings. UV radiation, responsible for fading colors in carpets, furniture, and wallpapers, is blocked up to 86 percent by low-E glass.
This UV-reflecting property is particularly beneficial for windows installed on the south and west sides of a home, where sun exposure is highest. By preventing almost 100% of UV radiation from reaching the interior, low-E windows from Safe and Sound Windows safeguard not only the aesthetic appeal of home furnishings but also contribute to the health and safety of the occupants by blocking harmful rays that can cause skin damage.
In summary, low-E glass offers a trifecta of benefits including improved insulation, enhanced energy efficiency, and superior UV protection, making it an ideal choice for homeowners and builders looking to optimize the performance of their windows while contributing to environmental conservation.
Different Glass Types for Different Needs
Here are some frequently asked questions
Low-E, standing for “low emissivity,” refers to a type of window glass coated with invisible metallic oxide layers. This special coating is designed to let natural light pass into your home while reflecting away ultraviolet (UV) rays and infrared light, keeping your space cooler and protecting it from sun damage.
One potential downside of low-E glass is its ability to block a certain amount of natural light compared to standard glass or open windows. This might be seen as a disadvantage in some scenarios. However, for many, especially in commercial settings, the benefit of UV protection and reduced heat entry outweighs the reduced natural light.
A notable issue with low-E glass is the possibility of it reflecting sunlight intensely enough to damage the siding of nearby buildings. This phenomenon happens when the sun’s rays hit a low-E window and then reflect onto a neighboring house, potentially causing vinyl siding to melt and distort from up to 20 feet away.
Emissivity in glass windows can vary significantly based on the type of glass and any coatings applied to it. For instance, standard uncoated glass typically has an emissivity of 0.84, indicating a higher level of heat transfer. In contrast, advanced products like Vitro Architectural Glass’s Solarban® 70 solar control glass boast an emissivity as low as 0.02, thanks to low-e coatings that significantly reduce heat transfer.
We Can Help You Choose the Right Glass for Your Home
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