Replacement window companies often describe sliding windows as double-hung windows turned on their sides: the sashes simply transfer to one or both sides as opposed to up and down. You can choose to have one or both sashes slide. During cleaning, the sashes hinge or lift out of the frame so you can do the job from inside your home.
With large, unblocked glass and plenty of airflow, quality replacement window companies like Lomax Window & Door Co. can furnish you with sliding windows that let light and air into large areas in your home. Since they don't open outwards to create an obstruction, these windows can be unobtrusively placed near busy spots like patios and porches.