Are Casement Windows Energy Efficient? Choose the Best Window Type from The Right Manufacturer

Depending on the way’s windows open, common types of windows are casement, double hung, awning, slider, bay bow, specialty, fixed windows. Casement window is one of popular window types in modern homes, so is fixed window. The following passages is going to introduce to you about energy efficient of casement window and fixed window.




According to Wikipedia, Casement window is “window that is attached to its frame by one or more hinges at the side. They are used singly or in pairs within a common frame, in which case they are hinged on the outside. Windows hinged at the top are referred to as awning windows, and ones hinged at the bottom are called hoppers. In other words, casement window is normally hinged at left or right with (concealed) hinges. It opens horizontally like a door, up to 180 degree. When it is hinged at the top or bottom, it opens vertically. When it’s hinged at the top, it is an awning, a hopper when bottom. As for casement stay, it is used to hold the sash in a specific open or closed position. In the USA, they uses a crank, but in parts of Europe they tend to use projection friction stays and espagnolette locking. The casement window is the dominant type in modern buildings in many other parts of Europe.


Fixed window is also called stationary or picture window, an inoperable window type or window doesn’t open, whose function is limited to allowing light to enter. Clerestory windows in church architecture are often fixed. Transom windows can be fixed sometimes. This type of window is used in situations where light or vision alone is needed it cannot open. It can be used separately to achieve the best air and water tightness as well as combination with another venting windows.




Energy efficiency of window is directly related to your bills when there is temperature difference between inside house and outside, typically in summer and winter time. The more energy efficient it is, the more energy bills you are saving. What affects energy efficiency? Is casement energy efficient? There are four main elements that affects energy efficiency. They are frame material, glass options, sealing and opening types.


FRAME MATERIALS are usually in vinyl, aluminum, fiberglass and wood. Of them, wood is the best frame materials due to its low thermal conductivity.


GLASS OPTIONS: The glass performance involves with U-factor, Solar Heat Gain Coefficient (SHGC), Visible Transmittance (VT). Generally, different areas require different U factor and SHGC, which is easy to check online. The lower U factor is, the better. SHGC and VT depend. Glass can be single-pane, double or triple pane. Double glazing is standard option people used to choose; triple pane is needed in higher performance requirements. Between the panel space, less conductive gas can be filled to reduce the heat or coldness. One of commonly used gas is argon gas. Low-e glass (low emissivity glass) and warm edge spacer can also help improve the energy efficiency.  


SEALING & OPENING TYPES: Sealing is related to the opening ways. There is no doubt that fixed window has the best sealing because it has the best air tightness and water tightness as it does not open. Among the opening windows, casement window has the best energy efficiency as there is not a track to slide on like slider or double hung.


Doorwin Casement window features double glazing, low-e coating and argon gas filled to achieve great energy efficiency, favored by many American homeowners. Independent testing by Intertek USA confirms that our products perform exceptionally well in all climate zones.  

Triple glazing and warm edge spacer are available for higher requirements. To find out more, visit .



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Hello Bella,

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Bella 1 day ago

I’d like to know more about windows with warm edge

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