First things first. What’s a slat? All horizontal window blinds (think: mini blinds, wood blinds, and faux wood blinds) have slats; they’re the strips of either metal, vinyl, wood or faux wood that open and close for light control.
Different blinds offer different slat sizes. Generally, faux wood blinds are offered with 2″ slats and 2-1/2″ slats. Doesn’t sound like too much of a difference but here’s the breakdown:
Faux wood blinds with 2″ slats are the traditional size and will work well with most window sizes. When fully tilted open, there will be a 2″ gap between the slats.
Faux wood blinds with 2-1/2″ slats are a good choice for larger windows. This is primarily because the larger slat size is more proportional to the window size – the larger slat size looks less busy on larger windows; larger slats also means fewer slats.
It is also true that larger slat size let in more light and provides greater view-through when the slats are tilted open. But this is independent of window size for some people. Some buy the larger slat size for average-sized windows just for greater view-through.