Low E-Glass Advantages & Disadvantages

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A type of window glass that has been used to minimize the transfer of heat is called Low Emissivity commonly known as Low E Glass.  This glass is made by using thin layer of material that is not seen by human eye including zinc, indium tin oxide and silver. The purpose of this layer is to reflect the harmful rays like Ultraviolet and infrared lights while allowing the visible sunlight to pass through.

The impressive solar grain structure effectively reduces the heat that can transfer between interior of building or home and external environment besides limiting the entry of infrared and UV rays. In summer due to presence of conventional window panes, the excessive hear enters into the building resultantly lead to increase in higher cost of cooling and energy consumption.

Hence, a low e glass acts as energy barrier to solar energy, reflections is achieved outside and helps to maintain a calm indoor temperature that is regulated by HVAC system.

Essentially, low-e glass acts as a barrier to solar energy, reflecting it back outside and helping to maintain a calm indoor temperature that is regulated by HVAC (heating, ventilation, and air conditioning) systems.

How Low E Glass Works:

A significant portion of a home’s energy loss, estimated between 10-50%, is attributed to windows and doors. Within this energy loss, approximately 90% occurs through the glass itself. This substantial amount of energy loss through a relatively small area of a house’s architecture prompted the introduction of the first low-emissivity glazing solution in 1975.

The ability to emit energy at a specific wave length is determined by the emissivity of surface in terms of thermal energy. The range of thermal emissivity is zero and one. Zero and one indicates perfect reflector and perfect absorber respectively. The other material has thermal emissivity less than 0.05 such as aluminum and silver. The emissivity of pure glass has value of 0.05 which reflects it most efficient material. Thermal energy with emissivity 0.9 allows 90% and reflects only 10% in case of standard glass.

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It becomes evident that window glass requires assistance in reflecting heat back into the home.

This is where low-e glass comes into play. Low-e glass is essentially regular clear glass with a microscopic, transparent coating on its surface that possesses better heat-reflecting properties than the glass itself. As a result, the composition of low-e glass has a lower emissivity compared to standard glass. By reflecting a higher proportion of heat back into the home, glass with a low-e coating helps maintain a warmer indoor environment. Additionally, it can also reflect solar thermal energy from the outside, thus keeping the interior cooler.

The coating used in soft-coat low-e glass units, which will be the focus here, typically consists of a low-emissivity metal such as silver.

Pros of Low E Glass:

Investing in low-e glass offers numerous compelling reasons that make it an attractive choice for individuals

 Energy Efficient

The primary advantage of investing in low-e windows is their high energy efficiency. Traditional windows allow for a two-way transfer of heat – while sunlight can warm a room, the heat generated inside can also escape through the glass, resulting in energy loss. In contrast, low-e windows minimize this heat transfer, preventing the loss of warmth from the room and reducing the amount of energy that needs to be expended on heating or cooling.

While the significance of heat loss through windows and doors may vary depending on the location and time of year, it becomes particularly problematic during winter in places like Regina. In such cold climates, when windows and doors allow heat to escape, it can have adverse effects on comfort, energy efficiency, home insulation, and financial expenses.

Ultraviolet Protection

Too much ultraviolet (UV) radiation negatively affects not only human health, but also fabrics and finishes. Prolonged UV exposure can fade or damage interior materials such as rugs, sofas, chairs, and artwork. By limiting the entry of UV light into a home, low-e glass helps extend the lifespan of these furnishings, particularly those made of fabric, by reducing fading and minimizing damage. This results in a longer-lasting and better-preserved appearance for your interior decor.

Highly efficient low-e windows are capable of blocking nearly 100% of UV radiation from entering your home.

the advantages include to ensure safety of family as well as protection of wooden furniture from tarnishing caused by UV rays.

Long Term Saving Of Cost

Investing in low-e windows can lead to long-term cost savings by reducing energy bills. The U.S. Department of Energy Efficiency and Renewable Energy highlights that low-e windows can decrease window energy usage by 30-40%. Considering that windows, doors, and skylights can account for up to 25% of a home’s energy loss, as stated by NRCan, purchasing low-e windows becomes a worthwhile option, especially when considering the age and condition of your existing windows.

Sound Insulation

One of the primary benefits of low-e glass is its exceptional insulating capability, surpassing that of standard uncoated glass. The inclusion of a low-emissivity film in low-e glass enhances its insulated properties, providing increased warmth during harsh British winters and improving the comfort of the home’s occupants.

By incorporating a soft-coat low-e film, the glass can achieve an impressively low emissivity of 0.05. When combined with other insulation technologies like warm-edge spacer bars and argon gas-filled cavities, low-e glass becomes a key component of creating highly effective insulated glass units (IGUs). Double-glazed units utilizing low-e glass and these insulation features can achieve remarkably low U-values, even as low as 0.9.

In practical terms, opting for low-e glass can help address the issue of family members constantly adjusting the thermostat. With the enhanced warmth provided by low-e glass from November to March, conflicts over thermostat settings can be significantly reduced.

The insulation power of low-e glass serves as the foundation for numerous other advantages, making it a compelling choice for window installations.


The reflective properties of low-e coatings extend beyond insulation and have a significant impact on solar radiation. During the sunny months between May and September, when the sun emits various forms of radiation towards your double pane windows, low-e coatings play a crucial role in mitigating the heat gain and preventing uncomfortably warm indoor conditions.

To achieve the desired effect, the soft-coat low-e surface layer is positioned within an insulated glass unit (IGU). When observing a double-glazed window from the outside, the outer and inner surfaces are not accessible for the coating. This leaves the two sealed internal surfaces, with the low-e coating typically applied to the inner surface of the inner pane.

Placing the low-e coating in this position provides optical benefits and reduces solar heat gain within the IGU. Similar to how low-e glass reflects heat back into the house, it also reflects thermal energy from the sun away from your home. Combining a low-e coating with a tint is often referred to as “solar glass,” which can achieve a low solar heat gain coefficient (g-value) as low as 0.14. This means that 86% of solar thermal energy is reflected away from your home, resulting in a cool and comfortable indoor environment during the summer. This is another significant advantage of low-e glass.

To illustrate the practical implications, consider the scenario of children taking their time to eat ice creams. With the reflective properties of low-e glass, there may be a longer refractory period between the initial scoop and the first drip, as the indoor temperatures remain comfortable and help prevent the ice cream from melting too quickly and causing messy situations on clothes, floors, furniture, or even the family pet.

Environmental Benefits

By choosing Low E glass for your windows, you contribute to a greener and more sustainable future.

The unique Design and Structure make this product to become energy efficient but also reduction the amount of heating and cooling as a result there is lower carbon emission.

Additionally, the enhanced insulation provided by Low E glass reduces reliance on artificial heating and cooling systems, leading to reduced energy consumption and a smaller ecological footprint.

2. Enhanced Comfort

With Low E glass, you can say goodbye to uncomfortable drafts near windows. Its insulating properties help create a more stable indoor environment by reducing heat transfer. This translates to improved comfort, as the glass acts as a barrier against cold outdoor temperatures and the radiant heat from direct sunlight.

4. Reduced Condensation

Condensation on windows can lead to various problems, including mold growth and damage to surrounding structures. Low E glass significantly reduces condensation by maintaining higher surface temperatures.

it strain grain structure helps to reduce temperature difference for humid climates having high moisture content and is achieved due to difference of temperature between indoor environment and glass.

Cons of Low E Glass

1. Higher Cost

Initially, the cost of soft-coat low-e glass units can be perceived as a disadvantage. We all prefer to avoid unnecessary expenses, especially when there are cheaper alternatives available. Soft-coat low-e glass tends to have a higher price tag compared to standard uncoated toughened glass units.

However, despite the initial higher cost, investing in low-e glass can lead to long-term savings on heating bills. This is due to its superior thermal insulation properties when compared to standard uncoated glass. While opting for standard glass may seem more cost-effective upfront, its inferior insulating ability can result in higher heating expenses in the future. Therefore, the money saved initially on installing standard glass may be offset by increased heating costs over time.

Compared to regular glass, Low E glass comes at a higher price point. The additional manufacturing processes and the specialized coatings involved in its production contribute to the increased cost. However, it is essential to consider the long-term savings on energy bills and potential rebates or incentives that may offset the initial investment.

2. Limited Solar Heat Gain

One potential drawback of low-e glass can be viewed as both an advantage and a disadvantage, depending on one’s perspective. It pertains to the reduction of natural light entering your home through these particular windows. The extent of light reduction can vary, ranging from a 25% to an 85% decrease, depending on the specific specifications of the chosen units.

However, this reduction in natural light transmission can also be seen as advantageous. It helps mitigate issues associated with excessive glare, as well as the increased entry of UV and thermal radiation into your living space. With low-e glass, you have the freedom to choose between a slightly dimmer, glare-free ambiance when the windows are closed or open them to allow ample natural light to illuminate the room.

While Low E glass effectively reduces heat transfer from outside, it also limits solar heat gain from the sun. In colder climates or during the winter months, some homeowners may prefer windows that allow more sunlight in to help naturally warm the interior space. It’s crucial to strike a balance between energy efficiency and desired solar heat gain based on your specific climate and heating requirements.

3. Potential for Exterior Reflections

In certain lighting conditions, Low E glass may produce exterior reflections. This can be a concern if the reflections interfere with neighboring properties or cause glare issues. However, advancements in Low E glass technology have significantly minimized this problem, and specific glass types are available that further reduce exterior reflections.

4. Installation Challenges

The installation of Low E glass requires careful handling and attention to detail.

In order to prevent the damage it is desired to install the installation as per the specification because the coating is of delicate one and costly as well.

This may require specialized training or hiring experienced professionals for the installation process.

5. Maintenance Considerations

Low E glass may require specific cleaning methods to avoid damaging the coating. Abrasive cleaners or materials can potentially scratch or degrade the coating, reducing its effectiveness. It is advisable to consult the manufacturer’s guidelines or seek professional advice to ensure proper maintenance and longevity of the Low E glass.


Low E glass offers numerous advantages for energy-conscious homeowners and builders.

The unique ability of Low E Glass to enhance comfort, efficiency and protection from UV makes it lucrative option for windows and other glazing applications. It is utmost desired to consider the factors like installation challenges, cost, requirement of maintenance, solar heat gain before making any reliable decisions.

With careful consideration of your specific needs, climate, and budget, Low E glass can significantly contribute to creating an energy-efficient, comfortable, and environmentally friendly living space.

David Noah

Howdy, I’m Noah Although I don't like all this internet thing but I love sharing my stories on the roof here. With my years of experience in number of roofing contractors across various boroughs of Florida, I'm here to answer all your roofing questions. I'm really honored to have you on my website browsing through our articles and hope you'll enjoy your visit and find my content helpful in every situation. You can contact me right away to discuss any of your roofing problem.

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