Sizing egress window wells and covers for a Louisville basement
Thirty-six inches of projection from the wall is the minimum, and the well has to be at least as wide as the window opening. Deeper wells need a way up, which means a permanent ladder or moulded steps rather than something leaning against the wall.
Corrugated steel wells are the cheap standard. Moulded composite wells with built-in steps look better and last longer against Kentucky clay. Poured or block wells get built where the situation is unusual.