My mother had gone to sears and she said they didn't have what she
needed. I went to home depot and explained I had a box type and the
guy gave me a unit, and I had very little time to install it. I just
plunked it in. later my mother looked at the instructions and saw it
vents to the side. The unit leaves an extra 5 or 6 inches as it is not
as wide as the box. Either that would be sufficient or I may cut out a
hole in the box sides to vent it, and figure out a way to insulate
around it farther forward or back from the side vents for winter.
Either that or I would return it, but what stores might have through
wall units ?