If a basement concrete wall is 43 inches tall, is it possible to put in an egress window?
Yes, you can install a code approved "egress opening"...but remember 1) sill from finish floor is 44", but you can raise the floor finish to accommodate the window frame, trim, etc., 2) overall opening must be 5.7 square feet (or 5.0 square feet if window is at grade), 3) minimum width must be 20", 4) minimum height must be 25", and 5) if a window well is required, it must be 9 square feet in area and project a minimum of 3' out. If the window well is more than 44" deep, then a ladder must be provided to the top. (See ICC R-310.1 - 310.2)