I really like this A/C unit and its width is exactly the width of my window panel (21.5"), but the "Window opening minimum width" in the specs is 23". From what I've seen in the Q&A for this Frigidaire unit, is that
The side panels, fully compressed, add 2" to each side. However, other A/C units (LG), on the same retailer site, have their width equal to the window open minimum.
Are side panels necessary?