Commercial and Residential Glass Installer and Manufacturer Resource

Low-e Glass IGUs: Efficiency and Functionality

Oct 14, 2020 12:00:00 PM / by Greg Martell


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, insulated glass units (IGU) with low-e glass are designed to be a barrier from sunlight and cold drafts. 

With enhanced insulating properties against the elements, low-e glass IGUs reduce your utility bills.

How Are Low-E Glass IGUs 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 an IGU with low-e glass, 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 an 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. 


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 light

Low-e glass is excellent for:

  • Glass doors
  • Glass walls
  • Greenhouses


Low-e Glass IGUs: 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

Topics: Coated glass, Low-e Glass, IGU

Written by Greg Martell