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Are Casement Windows Energy Efficient?

April 25, 2019

Casement windows (also referred to as crank windows, awning windows, or hopper windows) are attached to their frames with hinges. These hinges can be located on the sides, top, or bottom. These types of windows can have a much tighter seal than their traditional sliding counterparts, which can make them some of the most energy efficient types of windows on the market. Here’s a closer look at just how they operate with such efficiency.

Tighter Seals

Because casement windows do not depend on a rail system, their seals are tighter than those found on windows with sliding mechanisms. Simply due to their design, window rails can allow air leakage. The opening and closing motion causes air to find its way through the tiny cracks that are needed for the rail movement. This system of motion is demonstrably different from casement windows, though. When a casement window is pulled shut, it creates a seal against the frame that wind is unable to penetrate.

Low-E Glass

Aside from the airtight structure of casement windows, it’s also helpful to look at the window glass on its own merits. Low-E (emissivity) is a treatment used on glass to allow visibility while simultaneously blocking harmful UV rays. Most casement windows have this feature for better energy efficiency. Energy loss is said to decrease by 30 to 50 percent after this treatment, and many window companies don’t even offer casement windows without this energy efficient benefit. The downside to low-E glass is the initial cost, with cheaper casement windows sometimes not offering this feature. Expect to pay 10 to 20 percent more for low-E glass.

Argon Gas Infill

Argon gas is used to increase the thermal performance of glass. Many casement windows have a high R-value (a measure of insulation capacity) due to this added infill. The percentage of argon gas fill can increase the R-value of a window by up to 67 percent.

Double Pane

You may think that a double pane window in a casement window is beneficial simply due to the extra glass. However, it is a combination of glazing and argon gas infill that is responsible for the additional insulation. New technology and rigorous testing have proven that the performance of double panes plus sealant materials result in better energy efficiency.Casement windows are beautiful, easy to operate, and one of the most energy efficient types of windows on the market today. Whether you are looking for good airflow, increased visibility, or durability, they offer many valuable benefits. And when compared to traditional sliding units, casement windows can sometimes offer significantly greater energy efficiency. For any further questions about windows and energy efficiency, contact Green Energy of San Antonio today! Ask about receiving a free estimate, and see how we can start getting you big savings on your monthly energy bills.