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Low E Glass Window Replacement

Last updated on 03/23/2023

Did you know that roughly 33% of all heat loss in homes during winter months occurs through windows?

Windows offer the least resistance to heat loss, and they make up a large portion of the exterior surface area of our homes. They are also responsible for absorbing heat-generating infrared rays and damaging UV rays.

The solution? Low-E glass.

Low-E glass is engineered to combat some of the negative thermal effects of windows. They help to reflect heat in hot months and trap warmth in cold months. They can also protect your furniture and floors from sun damage and lower your energy bills.

Are you curious to find out what low-E glass is, how it's made, and its benefits? Keep reading to learn more.

What Is Low-E Glass?

Low-E glass stands for "low-emissivity" glass. The emissivity of a substance is its level of effectiveness at emitting thermal radiation.

In other words, low-E glass does not emit high levels of thermal radiation.

Low-E glass contains an invisible, transparent coating which reduces the glass's ability to emit thermal radiation. Instead of emitting radiant energy into your home, Low-E glass reflects it back into the environment.

Low-E glass can also prevent heat loss from your home, by reflecting radiant heat rays back inside rather than letting them out through your windows.

Low E Glass Windows

Types of Low-E Glass

There are two main types of low-E glass. These are:

Let's take a look at the differences between these two types of low-E glass and their applications.

Hard-Coat Low-E Glass

Hard-coat low-E glass has a higher thermal emissivity than soft-coat low-E glass. Hard-coat low-E glass allows some of the sun's short-wave infrared energy to enter your home through your windows.

This is advantageous in very cold climates where summers are short and mild. During the winter, your windows will help to trap thermal heat in your home.

Hard-coat low-E glass will also reflect long-wave heat energy from inside your home back into the interior, instead of letting it escape through the glass.

Soft-Coat Low-E Glass

Soft-coat or solar control low-E glass blocks even more infrared and UV rays than hard-coat low-E glass and has a higher U-value. U-value ratings indicate how much heat loss a window allows.

Soft-coat low-E glass is ideal for predominantly warm climates where you want to stop as much heat from entering your home as possible.

At the same time, soft-coat low-E glass will also help prevent the inside temperature from transferring through your windows to the outside, which helps to stabilize temperature levels in your home.

How Low-E Glass Is Produced

Low-E glass is produced by adding a microscopically thin layer of reflective material to glass panes. This layer lies on the inside of double- or triple-glazed glass windows, where it's protected from scratches and wear.

Passive, hard-coat low-E glass is manufactured via a pyrolytic process. Manufacturers apply a pyrolytic coating to glass sheets while they are in the float line. Because the glass is still forming, this allows the coating to fuse onto the glass sheet's surface.

This creates a strong, durable bond, hence the term "hard-coat."

Soft-coat low-E glass is produced via a room-temperature process where manufacturers apply a coating to pre-cut pieces of glass in a vacuum chamber.

The Benefits of Low-E Glass

Thanks to its reflective properties, low-E glass can help to regulate the temperature in your home. This can result in substantial energy savings.

According to, low-E glass windows can reduce energy loss in homes by 30% to 50%.

Besides moderating the temperature in your home and lowering your energy bill, low-E glass can also significantly reduce fading and sun damage on furniture, decor, and flooring. This is because all types of low-E glass block a certain amount of UV rays, which are responsible for sun-related damage.

Disadvantages of Low-E Glass

If you are wondering what the disadvantages of low-E glass are, the main drawback is that it costs more than regular windows. However, the extra cost can be more than offset over time by the energy savings low-E glass can achieve.

Another potential con is that soft-coat types of low-E glass can be so efficient at blocking infrared rays that areas in front of southern-facing windows (that are usually warm) might be too cool. The key to avoiding this is choosing the right types of low-E glass for your climate.

Low-E Glass vs Double Glazing

Currently, the industry standard for efficient windows is a combination of double- or triple-glazed glass, with low-E coatings. However, if you're choosing between one or the other, and want a double glazing vs low-E glass comparison, here's how they compare.

Although double-glazed glass is insulating, it does not reflect back heat. Therefore, when the sun hits double-glazed windows, they allow a higher amount of thermal energy into your home.

In contrast, low-E glass blocks a large portion of this infrared heat.

The Cost of Low-E Glass

Low-E glass takes more materials, time, and energy to produce, and therefore comes with a slightly higher price tag.

Most types of low-E glass cost between 10% to 15% more than regular windows.

While you will pay more if you opt to install new low-E glass windows in your home, you'll probably be able to recoup this cost in utility bill savings over time, especially if you heat or cool your home for a large portion of the year.

Are You Looking to Install Low-E Glass Windows in Your Home?

Low-E glass can regulate the temperature in your home, lower your energy consumption, and protect your furniture, flooring, and decor from UV damage.

Are you thinking about installing low-E glass windows in your home? If so, we can help you find the right installer through our quote feature at the top of this page.

Simply head to the beginning of this page and enter your zip code to get three quotes in under 60 seconds.

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