Windows are the kind of thing that are generally built locally for multiple reasons. So your experience will vary greatly based on what the window factory in your area is doing.
Where I live, single hung windows (only one sash) are most common, so only one screen is needed. Double hung windows are less common because people don’t want to pay for the expense of the additional sash (a lot of springs and mechanisms needed for a sash). A screen is an expense too, but nowhere near the expense of an additional shaft. Possibly the intent was to allow for opening the top to making cleaning easier, but that’s usually accomplished by having the top “fixed” portion of the single hung window be able to tilt out because putting all the springs and mechanisms for an additional sash for a feature to make it easier to clean isn’t necessary.
Yeah… I worked at a window factory before. The calculations needed to figure out the tension needed on the springs so that it will counter the weight of the sash was fun.
oatscoop@midwest.social 9 months ago
If you get windows one step above “cheapest available” you get a moveable screen.