Selecting a window seems simple when you think about it, but then you start looking at them and see all the different types and styles and it becomes difficult to know what you actually want for choosing energy efficient windows. The basic fact of the matter is that the best window depends on what is important to you; your individual circumstances are the single most important factor to consider. First option is the double hung sash window, this type of window consists of two panes; one above the other. The name sash comes from the band that exists between the two panes of glass; this is most commonly uPVC but can be wood too. Double hung also reflects on the two panes, meaning that both can be opened – the flexibility is useful. In general these are good windows for letting in a lot of light and depending on the particular one you choose (some are base hinged with a lock to stop them opening, some are sliding sash and some are side hinged to swing open) they can be as secure as you like. If security is important to you it is recommended that you install your windows with a lock to limit how wide they can be opened. A single hung sash window (again two panes one on top of the other) is much like the double hung but only one of the panes can be opened. Which one depends on the design you select and of course this will impact on the use of the window in the room and the flexibility around the window. For providing long term ventilation the upper pane is recommended, allowing a near constant circulation of air around the room, for an easy to open quick cooling draft occasionally the lower pane is recommended. If security is important to you the upper pane is recommended as the opening pane, as this is harder to reach and certainly harder to get through. The horizontal sliding sash window, as the name suggests, consists of two areas of glass, placed horizontally alongside one another, these are separated by a sash (though horizontal unlike with the hung windows) made of either wood or uPVC. These windows can only slide and either one or both panes will slide depending on the design, allowing you to dictate which side is open. Of course at no point can both sides be open simultaneously. These let in a lot of light and can usually open a lot wider, large sliding sash windows are poor for security and not recommended for ground floor windows, however the large amount of light and wide opening makes them a good choice for offices and homes that become overheated easily. Casement windows come in the largest variety of styles and designs and generally provide the most attractive choice in windows. These are hinged to the frame (usually at the side) and swing open; they can consist of either one or two panes and vary in size and shape. These are a popular choice for homes being easy to secure and lock as well as being better looking on the whole. The range of designs available can also help to make them popular. Regardless of which window design you select you should consider materials – uPVC is longer lasting, cheaper and more durable however wood is a more natural and traditional option that produces a more attractive window. Author Bio: Jake writes for easy windows quotes where he researches the prices of windows according to their quality and type.