If you ever heard about double hung window designs, then you must know about single hung window designs. Single hung window designs can be significantly less expensive than a double-hung design. Single-hung window designs look similar to double-hung windows and can be just as stylish and attractive. Like other windows, these window designs are available in frames of wood, aluminum and vinyl. Single hung window not only cheaper than double hung, but also considered to be extremely energy efficient. The slightly better option in this category because they have fewer moving parts and are thus less susceptible to leak hot and cool air through their seams.