Low E Glass: What Is It, How Does it Work, & Is It Worth It?

25 Nov.,2022


low-e glass vs clear

The Homeowners Guide to Low E Glass

Low E glass windows are all the rage these days, a gold standard for truly energy efficient homes. But is Low E glass worth it? Do the windows even work? How? Do you know if you already have them? 

Learn all this and more in our ultimate guide to Low E glass windows. 


What is Low E Glass?

Low Emissivity Glass, also known as Low E glass, is glass that has a coating applied to it, making windows and doors substantially more energy efficient. Originally designed to keep in infrared light for colder climates, they’re now a cost-efficient option that is effective in a variety of regions. Low E glass has a colorless, ultra-thin (thinner than a strand of human hair!), non-toxic coating applied that minimizes how much ultraviolet light passes through. Low E glass windows can drastically improve lighting while reducing heating and cooling costs. 


Windows are a huge investment in any home or structure, so whether you’re building new, or replacing or upgrading windows in an existing home or building, considering the benefits of Low E glass can have a big payoff, literally. 


How Does Low E Glass Work?

Low E glass works because of an application of microscopic layers of a reflective coating on the glass. The “E” stands for emissivity, which allows a material (in this case, the coating) to radiate energy. So, homes and buildings with Low E glass windows are able to keep the heat in during cold winter months, and let it bounce off during warm summer months. 


Think of Low E glass like the silver lining inside a thermos. When warm items are inside, heat bounces off the silver lining and reflects back inside the container to keep contents warm. This would be just like heat inside your home during the cooler months of the year. And, the opposite applies when you have cold items inside the thermos - heat doesn’t penetrate through the silver lining. So in the summer months, the outside heat can bounce or reflect off the Low E glass window, keeping your home cooler and reducing overall cooling costs. 


Do I Already Have Low E Glass?

Wondering if you already have Low E glass windows in your home? If your house is less than a couple decades old, or if your windows have been replaced, you might already have them installed. Luckily, there’s a very simple way for you to determine if your windows are, in fact, Low E glass. 

  1. Hold a lit match or lighter in front of the window

  2. Look for the image of the four flames that reflects in the glass

  3. If you have Low E glass windows: one of the images you see will be a different color than the others

  4. If you do not have Low E glass windows: all the images of the flame will appear the same color


Are Low E Glass Windows Worth It?

While they can be a slightly bigger investment than regular glass windows, depending on where you live, Low E glass can be well worth the cost. They give you the look of beautiful, nice, new windows, with the added benefit of reducing energy costs. When you consider the fact that they’re really only a few extra dollars each when compared to regular glass, we’d argue that they’ll pay for themselves quickly once you factor in what you’re saving on your heating and cooling bills year-round. According to Energy.gov, between 25-30 percent of your heating and cooling use is due to heat loss and heat gain through windows - it’s not hard to see how quickly the savings can add up!


Where are Low E glass windows a good investment? 

If you live in cold, northern climates, Low E coatings can be applied to stop heat from escaping. And if you live in warm, southern climates, Low E coatings are effective at blocking the heat from entering your home. So really, Low E glass windows can be a sound investment regardless of where you live. 


Other Energy Saving Window Features

Low E glass windows aren’t the only aspect you may want to consider if you’re striving to reduce your energy costs. Any of the following window qualities can be helpful, too.


Condensation Reduction

Warm Edge Spacer Systems are different from traditional spacers like aluminum. While aluminum spacers lead to heat loss and excess condensation, the innovative Warm Edge Spacer System allows for flex with the window as temperatures change. The result? Better insulation and reduced sealant failure, which can translate to energy cost savings. 




Argon Spacing

Argon gas can be used in thermal windows to enhance performance, reduce condensation and frost, improve soundproofing and minimize heat loss through the glass. It’s beneficial in any climate, and for optimal cost savings and efficiency, can be combined with Low E glass.  


How to Get Low E Glass Windows

Ready to get started with windows that do the double duty of looking beautiful and saving you money? Window World has all the features of the newest technology and energy efficient glass and windows available. Reach out today for a free quote. We handle everything - from ordering to installing windows you’ll love, with cost savings that’ll leave you wondering: why did we wait so long to do this?! Request a quote today to learn more.