Commercial and Residential Glass Installer and Manufacturer Resource

Window Coating: An Introduction to Coated Glass

Nov 29, 2023 9:03:00 AM / by Greg Martell


A window is so much more than an opening in a wall. It’s a source of natural light and ventilation and can provide a beautiful view of the surrounding landscape.

Windows can also control lighting, provide comfort by regulating heat, and protect against harmful UV rays. With the right window coating, you can take a basic commercial glass project to one that makes your customers safe and comfortable

Let’s dig into the basics of coated glass to see which type of coating is right for your project. 

Window Coating | What is Coated Glass?

Coated glass is treated with a thin layer of metallic or ceramic material. This process can be done during manufacturing or applied as a film after the glass is already installed. Coated glass is available in different types and offers a range of benefits.

Types of Window Coating

There are many different types of glass coatings available, each with its own unique benefits and applications. Some of the most common types of window coatings include:

  • Low-emissivity (low-E coating) glass: This coating helps to reduce the amount of heat transfer through the glass, making it more energy-efficient.
  • Reflective glass: As the name suggests, this coating reflects a significant amount of sunlight and reduces glare. It’s often found in buildings with large windows or where excessive sunlight can be an issue.
  • Self-cleaning glass: This coating uses a photocatalytic process to break down organic materials, making the glass easier to clean and maintain.
  • Tinted glass: Tinted coatings can help reduce the amount of sunlight entering a building, providing both energy efficiency and improved comfort for occupants.
  • Ceramic glass coating: A more recent development in window coatings, ceramic glass offers high strength and durability while also providing energy efficiency.
  • Insulated glass (IGU): IGUs consist of two or more panes of glass with a layer of air or gas between them, providing better insulation and energy efficiency.


Benefits of Coated Glass

Coated glass offers a variety of benefits that can make it a good choice for a variety of applications.

Examples of how coated glass can be used to improve the performance and appearance of buildings include:

  • Improved energy efficiency: Low-emissivity (low-E) glass is coated with a thin layer of metal that reflects infrared radiation, or heat. This helps keep buildings cool in the summer and warm in the winter, which can lead to significant energy savings.
  • Glare reduction: Coated glass with reflective or tinted coatings can help reduce glare, making it easier for employees to work without being affected by excessive sunlight.
  • Enhanced comfort: By reducing heat transfer and glare, coated glass can create a more comfortable interior environment for building occupants.
  • Light reduction: A tinted glass window is coated with a thin layer of dye that gives it a colored appearance. Tinted glass can be used to reduce glare, improve privacy, and block UV rays.
  • UV ray protection: UV-protected glass is coated with a thin layer of material that blocks ultraviolet radiation. UV-protected glass can help to protect people and furniture from the harmful effects of UV rays.
  • Durability against the elements: Coated glass can be made to be more durable against the elements, such as rain, wind, and snow. This makes it a good choice for use in exterior applications.
  • Enhanced strength: Coated glass can be made stronger than standard glass, making it less prone to breakage and damage. This makes it a good choice for use in applications where safety is a concern, such as in glass showers, storefronts, and skylights.
  • Better scratch resistance than off-line coated products: Glass that is coated during the manufacturing process (online coated glass) is typically more scratch-resistant than glass that is coated after manufacturing (offline coated glass – more on that below). This makes online coated glass a good choice for applications where the glass is likely to be scratched, such as in shower doors and kitchen countertops.


Coated Glass Applications

Coated glass is a versatile and innovative material with a wide range of applications. Commercial applications include:

  • Office buildings: Coated glass can help create a more energy-efficient and comfortable workspace for employees. It can also enhance the appearance of a building, making it more attractive to potential clients.
  • Retail stores: Coated glass is often used in storefront windows to reduce glare and provide better insulation for climate control.
  • Hotels: Coated glass can help create a more comfortable and energy-efficient environment for hotel guests while also improving the overall aesthetics of the building.
  • Hospitals and healthcare facilities: Coated glass with self-cleaning properties can help reduce maintenance and cleaning costs in healthcare settings where cleanliness is crucial.


Online and Offline Coated Glass | What’s the Difference?

You may hear people refer to online and offline coated glass (as we did above). The main difference between offline and online coated glass is the manufacturing process. Offline coated glass is coated after it is manufactured, while online coated glass is coated during the manufacturing process.

Offline coated glass is coated using a variety of methods, including sputter coating, chemical vapor deposition (CVD), and sol-gel. These methods can be used to apply a wide range of coatings to glass, including:

  • Low-E coatings 
  • Reflective coatings
  • Self-cleaning coatings
  • Tinted coatings 

Offline coated glass is typically more expensive than online coated glass, but it offers a wider range of coating options and can be used on glass of any thickness.

Online coated glass is coated with a pyrolytic coating. This process involves applying a thin layer of metal to the glass while it is still hot from manufacturing. The metal is then bonded to the glass using a chemical reaction. Online coated glass is typically less expensive than offline coated glass, but it is limited to a smaller range of coating options and can only be used to coat glass up to a certain thickness.


Coated Glass Type

Offline coated glass

Online coated glass

Manufacturing process

Coated after manufacturing

Coated during manufacturing

Coating methods

Sputtering, CVD, sol-gel

Pyrolytic coating

Range of coating options



Thickness of glass that can be coated

Any thickness

Up to a certain thickness


More expensive

Less expensive


Which Type of Window Coating is Right for You?

The best type of coated glass for you will depend on your specific needs and budget. If you are unsure which type of coated glass is right for you, it is best to consult with a glass expert.

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Written by Greg Martell