What is Insulated Glass?

When purchasing a new window for your home or business, you’ll likely come across the phrase “insulated glass.” This is a common phrase because insulated glass units are the preferred glass on the market today. As such, they come with a host of advantages that greatly benefit a home or business. However, you’ll also want to know about a couple of the disadvantages before purchasing, so you can ensure you’re buying the best type of glass that meets your needs.

Insulated Glass Pros

Temperature Control
Energy Efficiency
Sound Insulation
Reduces UV Rays
Safety and Security
Versatility

Insulated Glass Cons

Higher Initial Cost
Must Be Replaced if Damaged

When comparing the pros and cons side by side, it’s clear that the pros outweigh the cons of insulated glass. That’s because they are one of the best investments one can make for their home or business. But what exactly is insulated glass or an insulated glass unit? By learning the ins and outs of insulated glass panels, including what they are and their benefits, you’ll be more than prepared to upgrade your existing windows to high-quality insulated glass windows.

Insulated glass is a broad term to describe a few different types of glass, including low e glass, gas-filled glass, and heat-retention glass. However, insulated glass units (IGU) specifically refer to windows or door glass with two or more glass panes divided by an air space, such as double glazing windows (also known as double pane windows).

Insulated glass is often gas-filled glass, but not always. Some insulated glass units only contain air space rather than a gas insert. Though it is standard for an insulated glass unit to have a gas insert.

How is insulated glass made?

During the manufacturing process, gas is inserted between the glass panes via a small hole along the window spacer. The gas used in the window or door glass is typically krypton, argon, or a mixture of both. The type of gas used depends on the manufacturer.

The gas is inserted between each window pane, which is separated by an aluminum spacer bar. This spacer serves more than one purpose; it typically contains a desiccant, which is a drying agent to remove any moisture in the space between the glass panes that may be present during the initial manufacturing process, which could result in condensation. The spacer is sealed internally and externally to the window panes so that no air or moisture can enter the space. These sealants also prevent the gas from leaking out of the insulated glass unit.

The amount of space between the glazing is customizable, but typically ranges between 6mm to 20mm. The recommended amount of space between the panes for double glazing is 12mm, as this amount offers optimal thermal performance. Anything thicker than 20mm results in decreased insulation performance due to convection. Glass thickness is also customizable, and the thicker the glass, the more insulated it is.

The purpose of insulated glass is for enhanced thermal insulation performance. Residential windows will typically have insulated glass windows for increased energy efficiency. Large exterior doors with glass can also have insulated glass units. While increased insulation performance is the main advantage of insulated glass, they also benefit the home through their sound insulation, UV ray reduction, enhanced safety and security, as well as their versatility.

Pros of Insulated Glass

1. Temperature Control

The main function of insulating glass is its thermal performance, which describes how well it retains internal temperatures and how much it reduces heat transfer. A single pane window, for example, only contains one pane of glass. Thus, it does not contain an air space or gas-filled chamber. Because of this, it readily allows heat transfer through the glass, resulting in solar heat gain or heat loss. In other words, the home becomes heated from the warm sun shining through the windows, or internal heat is lost through the glass.

When heat transfer occurs, temperature fluctuation results. If the internal temperature of a home or business is constantly changing due to heat transfer, then the HVAC unit will constantly be running in an attempt to try and maintain the internal temperature.

Insulated glass units, on the other hand, significantly reduce heat transfer, resulting in steadier home temperatures and reduced energy costs. You can further increase thermal performance by upgrading to triple glazing or triple paned windows and choosing low e glass as your glass type.

2. Energy Efficiency

By maintaining steady internal temperatures, you ultimately increase your home’s energy efficiency. A home’s energy efficiency is dependent on how much energy or power is used to maintain the functionality of the home. The more energy used, the less energy efficient a home becomes.

As mentioned, insulated glass units create substantial thermal resistance: the hot or cold air outside cannot penetrate the barrier created by the insulated glass unit, and the internal temperature cannot fully escape through the double or triple glazing.
Shockingly, it’s estimated that about 90% of a home’s heat loss occurs through the window or door glass. Because of this, the heater in one’s home is constantly kicking on, especially in winter, to maintain the home's internal temperature.

By upgrading your windows with an insulated glass unit in the form of double glazing or triple glazing (and a low e coating), you significantly increase your home’s energy efficiency. Because the insulated glass unit reduces heat transfer, a home’s HVAC unit won’t have to turn on as frequently. Not only will this save you money on energy bills, but the energy-efficient window glazing also helps maintain the lifespan of your HVAC unit.

When you increase your home’s energy efficiency, you reduce your carbon footprint. Fossil fuels provide electricity to your HVAC system, and it’s estimated that the energy and fuel it takes to provide power to homes and businesses contribute up to 40% of carbon emissions. About 28% of carbon emissions come from the energy it takes to power HVAC systems alone. By simply investing in high-quality, energy efficient insulated glass panels, you contribute to lessening the impact of carbon emissions!

3. Sound Insulation

Another benefit of insulated glass units is a surprisingly lesser-known advantage: sound insulation. Insulated glass units significantly reduce noise because the sound waves have to pass through two or more layers of glass and the air/gas space between them. It’s estimated that double pane glass reduces noise by up to 60% compared to single glazing, and even more so with triple glazing.

External noise has a profound impact on the comfort and ease one feels in their home. This is especially true for those who live in the city, near an airport, highway, or train track. Constant noise can affect one’s sleep and increase stress, as it inhibits your ability to fully wind down and relax.

Thankfully, insulated glass reduces medium to high-frequency noises, including the human voice, vehicles, planes, trains, animals, and more. By increasing glass thickness and opting for triple glazing, you can further enhance your window's sound insulation abilities, resulting in a quieter and more peaceful home.

4. Reduces UV Rays

As with sound waves, insulated glass units can also reduce light waves—specifically UV rays and direct sunlight. UV stands for ultraviolet radiation, which naturally comes from the sun. UV rays can easily penetrate single paned windows, which can be a problem if you like to sit in the sun in your favorite chair next to the window. UV rays can also damage home furnishings, such as wooden furniture, decorations, photographs, colorful carpets, and couches, causing them to fade over time.

The two or more glass panes in an insulated glass unit and the gas-filled space between them reduce the amount of direct sunlight entering a space, which increases the lifespan and vibrancy of household items. Glazing options, such as low e insulated glass, further reduce UV rays. In this way, you can significantly enhance your window’s ability to block UV rays by upgrading to insulated glass units and using a special low e coating.

5. Safety and Security

Another lesser-known benefit of insulated glass units is their safety and security. If someone is trying to break into a home, they have to break both panes of glass, which can be difficult and time-consuming.

If you want your home windows to be even more secure, you can upgrade to insulated glass windows with tempered glass or laminated glass. Tempered glass and laminated glass are types of safety glass. They are very difficult to break, as they are extremely strong and impact resistant.

6. Versatility

As you may have discovered by now, insulated glass is highly versatile. This is because an insulated glass unit simply describes a window or door glass with two or more panes of glass and an air or gas space between them.

With an insulated glass unit, you can choose how many glass panes you want, the type of gas between them, glass thickness, space thickness, and glass type. You can also choose special coatings, such as low e glass. Furthermore, an insulated glass unit can be in any type of window, such as casement windows, double hung windows, and more. In this way, IG units are incredibly customizable, making them a versatile choice for your new windows or doors.

Insulated Glass Cons

1. Higher Initial Cost

Perhaps the greatest drawback when purchasing insulated glass is the initial cost. Insulated glass units are an investment because of their versatility and energy efficiency.

Even though insulated glass units are an investment upfront, they pay themselves back over time through lower energy bills every month. In this way, they cost more at first but will actually help you save money in the long run.

In comparison, a single pane window is much cheaper, but will significantly decrease your home’s energy efficiency. Decreased energy efficiency results in higher energy bills every month, and a higher likelihood that you’ll need to replace your HVAC system because it’s constantly running.

2. Must be Replaced If Damaged

Unfortunately, if an insulated glass unit is damaged, the individual piece cannot be fixed, and the entire unit will need to be replaced. If a glass pane breaks or the sealant is damaged, and condensation occurs between the glass panes, the single problem can’t be fixed: the entire window needs to be replaced.

This is because as soon as the gas escapes through broken glass or condensation occurs due to damaged sealant, the insulated glass unit is no longer performing as it should. Due to the precise manufacturing process when IG units are made, they cannot be repaired and need to be replaced.

Give Your Windows an Upgrade with Insulated Glass Today!

If you’re tired of old drafty windows and high energy costs, it may be time to give your home or business an upgrade with insulated glass windows.

Insulated glass benefits your space by increasing your home's energy efficiency and maintaining steady internal temperatures. They also reduce UV rays, provide sound insulation, and increase safety and security. And because of how versatile they are, you can customize your insulated glass unit to be exactly what you need!

Ready to design a high-quality window or door with insulated glass? Contact Rustica’s design team today to start your next project!