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Understanding Low-E Windows

With winter firmly upon us, the topic of heat loss from windows is top of mind for many across the country. Low-E windows are often touted as an effective way to minimize heat loss. In this post, we’ll explore what low-E windows are, how they work, and what role window film can play to help. Let’s get started!

What Are Low-E Windows?

Low-E windows, short for low-emissivity windows, are specially designed to minimize the amount of heat transfer through your windows. These windows are coated with a thin, virtually invisible layer of metallic particles that reflect heat either back into your home during the winter (to keep it warm) or away from your home during the summer (to keep it cool).

Emissivity, with respect to windows, refers to the ability of a surface or material to emit radiant energy in the form of heat. It is a critical factor in understanding how windows interact with heat and thermal energy. Emissivity is typically measured on a scale from 0 to 1, with lower values indicating lower emissivity and higher values indicating higher emissivity.

Read more about emissivity and how it relates to window film.

How Do Low-E Windows Work?

Low-E windows work based on the principles of radiant heat transfer. They have a low emissivity (emissivity refers to the ability of a surface to emit radiant energy), which means they don’t radiate heat effectively. Instead, they reflect heat back to the source.

Heat will be reflected differently, depending on the glass surface the low-E coating is placed on. According to Jeld-Wen, “low-E coatings can be applied to both the exterior and interior glass surfaces of a window or door and deliver comfort and energy savings in both directions. On an exterior glass surface, a Low-E coating can reflect the heat of the summer sun. On an interior surface, a Low-E coating reflects back the existing indoor temperature.”

This means depending on what part of the country you live in, window manufacturers will sell a different low-E window. In the winter, they will sell a window with the low-E coating on the interior panel which will keep the heat from your furnace inside. While in the summer, the window will have the low-E coating on the outside keeping the heat from the sun outside.

Benefits of Low-E Windows

Enhanced Energy Efficiency

Low-E windows significantly reduce heat loss in the winter and heat gain in the summer. This can lead to lower energy bills year-round.

Increased Comfort

With less temperature fluctuation near your windows, you’ll enjoy a more consistent indoor climate, free from drafts and hot spots.

UV Protection

Low-E coatings also block a significant amount of harmful UV rays, which can fade your furniture, flooring, and curtains over time.

Environmentally Friendly

Reduced energy consumption means a smaller carbon footprint, making Low-E windows an eco-friendly choice.

How Window Film Complements Low-E Windows

While Low-E windows are fantastic for energy efficiency, you can further enhance their performance with window film. Here’s how:

Solar Control Window Film

Solar control window film, like the products offered at Concord Window Film, can provide an extra layer of protection against heat gain and UV rays. By applying solar control film to your low-E windows, you’ll maximize their energy-saving potential. Learn more about solar control window film.

Privacy Window Film

Combine the benefits of low-E windows with matte white privacy film for added privacy without sacrificing natural light. Learn more about privacy window film.

Safety Film

Enhance the safety of your low-E windows with safety film, which holds glass together in case of breakage. Learn more about safety film.

It’s important to note that manufacturers of low-E films don’t publish numbers relating to the benefits of applying a low-E film to a low-E window. So, it’s unclear how much benefit you would get from doing it. Concord Window Film does not have a low-E window film offering. Learn more about low-E window film.


Low-E windows are a smart investment for homeowners in cold climates looking to improve energy efficiency and indoor comfort. And when you pair them with high-quality window film from Concord Window Film, you’ll enjoy even greater benefits. Whether you’re aiming to reduce energy bills, protect your furnishings, or enhance privacy, the combination of low-E windows and window film is a winning solution.

We hope you found this information helpful. If you have any questions or would like to explore our range of window films, visit us at

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