What is Low E Coating and How Does It Work?
As homeowners and builders become increasingly conscious of the importance of energy efficiency in windows, Low E coatings have emerged as a popular solution for improving their performance. In this comprehensive guide, we will delve into the world of Low E coatings, exploring their types, manufacturing processes, and benefits. Discover how these coatings can contribute to your home’s energy efficiency and comfort.
Table of Contents
2. What is Low E Coating?
a. Definition of Low E (low-emissivity) coating
Low E coatings are thin, transparent layers of metal or metallic oxide applied to window glass. Their primary purpose is to reduce the amount of heat transfer through windows, thus improving the overall energy efficiency of a building.
b. Brief history and development of Low E coatings
In the 1930s and 1940s, researchers started investigating the use of thin metal coatings on glass to improve its thermal properties. The energy crisis of the 1970s, spurred by rising oil prices and a growing awareness of the need for energy conservation, prompted renewed interest in developing energy-efficient solutions for buildings. However, it wasn’t until the late 1980s that these coatings gained widespread recognition and adoption due to advancement in technology.
C. Types of Low E coatings
Low E coatings can be broadly categorized into two types:
i. Passive Low E coatings (Low-E1)
Passive Low E coatings, also known as Low-E1, are designed to minimize heat loss in colder climates by reflecting heat back into the building. These coatings typically have a higher solar heat gain coefficient (SHGC) which means they allow more solar heat to pass through the glass. For example, a Low-E1 coated window could have a SHGC of around 0.50, which means that it allows 50% of the solar heat to pass through. The U-factor, a measure of heat transfer, for these windows can be as low as 0.28, indicating excellent insulation properties and reduced heat loss.
ii. Solar control Low E coatings (Low-E2 and Low-E3)
Solar control Low E coatings, including Low-E2 and Low-E3, are designed to reduce solar heat gain in warmer climates or for buildings with significant sun exposure. These coatings have a lower SHGC, meaning they allow less solar heat to pass through the glass. A typical Low-E2 coated window might have a SHGC of around 0.30, while a Low-E3 coated window could have an even lower SHGC of around 0.25. The U-factor for these windows can also be low, ranging from 0.28 to 0.30, indicating good insulation properties and energy efficiency.
By incorporating Low E coatings with optimal performance metrics, homeowners and building owners can achieve substantial energy savings and heat gain reduction, leading to a more comfortable and energy-efficient indoor environment.
3. Soft Coat vs. Hard Coat Low E Coatings and Manufacturing Process
a. Comparison of soft (sputter) and hard (pyrolytic) coatings
Soft coat Low E coatings, also known as sputter coatings, are created by depositing multiple layers of metal or metallic oxide onto the glass in a vacuum chamber. On the other hand, hard coat Low E coatings, or pyrolytic coatings, are formed by applying a thin layer of metal oxide directly onto the glass surface during the manufacturing process.
b. Pros and cons of each type
Soft coat Low E coatings generally offer superior performance in terms of energy efficiency, solar control, and UV protection. However, they can be more susceptible to damage and are therefore always coated on the interior facing side of a dual pane sealed unit. Hard coat Low E coatings, while not as efficient as soft coat coatings, are more durable and easier to handle.
c. Factors to consider when choosing between soft coat and hard coat
When deciding between soft coat and hard coat Low E coatings, factors such as climate, window orientation, and building design should be taken into consideration. Additionally, it is essential to weigh the performance benefits against the cost and durability of each type.
d. Different methods for applying Low E coatings
As mentioned earlier, there are two primary methods for applying Low E coatings:
i. Sputter coating
This process involves depositing multiple layers of metal or metallic oxide onto the glass surface in a vacuum chamber. Sputter coating is typically used to produce soft coat Low E coatings.
ii. Pyrolytic coating
Pyrolytic coating, also known as chemical vapor deposition, involves applying a thin layer of metal oxide directly onto the glass surface during the manufacturing process. This method is used for creating hard coat Low E coatings.
e. How the manufacturing process affects coating performance
The manufacturing process can have a significant impact on the performance of Low E coatings. Soft coat Low E coatings are generally more effective at reducing heat transfer, while hard coat Low E coatings are more durable and resistant to scratches and other damages. The choice between the two methods should be made based on factors such as the desired performance, climate, and specific requirements of the building.
4. How Does Low E Coating Work?
a. Explanation of emissivity and its role in heat transfer
Emissivity refers to the ability of a material to emit or absorb radiant energy. A low-emissivity material, like a Low E coated window, reflects more radiant heat than it absorbs, reducing the amount of heat transfer through the window.
b. The science behind Low E coating: reflecting and absorbing heat
Low E coatings work by reflecting and absorbing heat, depending on the type of coating used. Passive Low E coatings primarily reflect heat back into the building, while solar control Low E coatings reduce the amount of solar heat entering the building. The result is improved energy efficiency, as the interior temperature is better maintained and less reliant on heating or cooling systems.
c. Comparison of Low E coated windows with non-coated windows
Compared to non-coated windows, Low E coated windows offer several benefits, including:
- Improved energy efficiency, as they minimize heat loss and solar heat gain
- Enhanced comfort, due to better temperature regulation
- Reduced condensation and moisture-related issues
- Protection from harmful UV rays, which can cause fading and damage to furnishings
5. Benefits of Low E Coating
a. Improved energy efficiency
By reducing heat loss in winter and solar heat gain in summer, Low E coatings contribute to the overall energy efficiency of a building. This results in less reliance on heating and cooling systems, which can lead to substantial energy savings.
b. Lower energy bills for homeowners
Improved energy efficiency translates to lower energy bills for homeowners. By reducing the need for heating and cooling, Low E coated windows can help save on energy costs throughout the year.
c. Enhanced comfort
By maintaining a more consistent interior temperature, Low E coated windows contribute to a more comfortable living environment. This is particularly important in regions with extreme temperature fluctuations.
d. Reduced condensation and moisture-related issues
Low E coatings can help minimize condensation on windows, which can lead to mold, mildew, and other moisture-related issues. This not only contributes to a healthier living environment but also helps protect the structural integrity of the building.
e. Protection from UV rays and fading
Low E coatings block a significant portion of harmful UV rays, which can cause fading and damage to furnishings, flooring, and artwork. This added protection helps extend the lifespan of valuable belongings.
6. Leading Manufacturers of Low E Glass Products
a. Overview of major players in the industry
There are several well-established manufacturers of Low E glass products, each with their own unique offerings and technologies.
b. Cardinal Glass Industries
Cardinal Glass Industries is a leading manufacturer of Low E glass products. With a strong focus on research and development, the company has introduced numerous innovative technologies in the field of energy-efficient glass solutions.
c. PPG (now Vitro Architectural Glass)
PPG, now part of Vitro Architectural Glass, is another major player in the Low E glass industry. With a rich history in glass manufacturing and a commitment to sustainability, PPG offers a wide range of energy-efficient glass products for various applications.
7. The Importance of Proper Installation and Maintenance of Low E Coated Windows
a. Ensuring optimal performance
To maximize the benefits and performance of Low E coated windows, proper installation and maintenance are crucial. Choosing a reputable glass fabricator with experience in handling Low E coated windows can help ensure that they are correctly installed, sealed, and aligned for optimal performance. At Silverline, we have partnered with the leading glass fabricator Vitrum for all of our sealed unit supply.
b. Caring for Low E coated windows
Low E coated windows may require special care and cleaning techniques to prevent damage to the coating. It is essential to follow the manufacturer’s guidelines for cleaning and maintenance, using only approved cleaning products and methods. Regularly inspecting your windows for signs of wear or damage can help prolong the life of the coating and maintain its performance.
Low E coatings have become increasingly popular in the world of energy-efficient windows due to their numerous benefits, including improved energy efficiency, lower energy bills, enhanced comfort, and protection from UV rays. Understanding the differences between soft coat and hard coat Low E coatings, as well as the manufacturing processes and performance characteristics, can help you make an informed decision when choosing the best solution for your home or building.
Whether you are considering sliding windows, bay or bow windows, or any other window style, incorporating Low E coatings can significantly enhance their performance and contribute to a more comfortable and energy-efficient environment. To learn more about vinyl windows, the most popular window products on the market, visit Silver Line Exteriors and explore our extensive window features and offerings.
For more information on the installation process, window replacement, or to request an estimate, contact us today. Our team of experts is here to guide you through every step of the process and help you make the best choice for your home or building.