The others are 30" above if crawlers, or close to. The higher up you go, the more it costs to heat and cool.
If you want a finished basement........ a second means of escape required, all basements and bedrooms.
Window egress: 44" max. above finished floor, 5.7 min. clear opening EXC. 5. OK if direct grade access, Min. 20" wide---24" high , separate rules for window wells.
Anything less, putting someone in danger, in case of fire. Even after you sell the place.
So a 20" high window with 44" to the floor, = 66" Not legal for headroom, so it would not be habitable, or living space.
Run it by your Building Department for minimum safety code requirements. Be safe, G