Commercial and Residential Glass Installer and Manufacturer Resource

Low-e Insulated Glass Units: Efficiency and Functionality

Mar 14, 2022 12:00:00 PM / by Greg Martell

Low-e Insulated Glass Units

No one wants to spend more money than they have to in keeping a space’s temperature comfortable. 

That’s where low-e -- or low-emissivity -- glass comes in. 

Pairing the performance of standard glass sheets with energy efficiency, a low-e insulated glass unit (IGU) is designed to be a barrier from sunlight and cold drafts. 

With enhanced insulating properties against the elements, low-e glass IGUs reduce your hating and cooling costs.

What is Low-E Glass and How Are Low-E Glass Insulated Glass Units Manufactured?

Low-e glass is made by applying one or more ultra-thin coatings to a pane of glass. Each coating consists of an element that reflects ultraviolet rays and heat, as well as an outer layer that improves durability

In creating a low-e IGU, a narrow strip of coating around the perimeter of a pane’s edge is removed. This allows sealants to directly bond to a piece of glass and prevents coating corrosion

To maximize efficiency and increase insulation, the space between panes is filled with inert gas and sealed. Common inert gasses in IGUs include:

  • Argon
  • Krypton 
  • Xenon 

Argon is most often used in low-e glass IGUs, as it’s the most affordable. 

Resource: Want to know what a glass fabricator is capable of? Download our Services & Capabilities guide:

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What Types of Low-E Glass Are Available for IGUs?

There are two types of low-e glass used in IGUs: pyrolytic hard coat and soft coat. 

During manufacturing, a single layer of low-e coating is applied to a pane of what will become pyrolytic hard coat low-e glass. As the coating and glass cool, they fuse. This process makes the low-e coating more durable, but slightly less energy efficient. That’s why pyrolytic hard coat low-e glass is used for exterior windows in environments where harsh weather and strong winds are common. 

A more efficient product, soft coat low-e glass requires a bit more skill during manufacturing. Once a glass pane is cooled and washed, several low-e coatings are applied to its surfaces immediately before going into an IGU. With its additional layers of coating, soft coat low-e glass offers more protection from UV rays and solar heat gain. 

Some of the highest-performing soft coat low-e glass is made with a double or triple layer of silver. Of note, silver is especially challenging to work with and must be handled by an experienced and certified professional.

Beyond the IGU: Low-E Glass Applications

Anywhere energy efficiency is a must, low-e glass is practical. In some cases, state and/or local codes require low-e glass.

Even when not required, low-e glass is still helpful because it reduces drafts, lowers utility bills, and blocks harmful UV rays. All the while, low-e glass still lets in plenty of visible natural light.

Low-e glass is excellent for:

  • Glass doors
  • Glass windows
  • Glass walls
  • Greenhouses

Low-e Insulated Glass Units: An Investment in Savings 

Regardless of climate, low-e glass IGUs help you maintain a consistent temperature in just about any space. In other words, low-e glass keeps both the cold and heat where it belongs -- outside. 

Your thermostat can remain relatively untouched, no matter the season. 

Interested in using low-e glass IGUs to reduce utility bills?

Contact New Angle Beveling

(Editor's note: This article was originally published in October 2020 and was recently updated).

Topics: Coated glass, Low-e Glass, IGU

Written by Greg Martell