These are 48" x 48" sliding windows, not doors!
And, at $149 per window, these U-0.30 windows are only $9.31 per square foot!
Since they are under a nice 12" over-hang that prevents water drip and snow build-up,
not exposed to a lot of sun during the day (Not facing south), they should last at least 20 years.
At which time I should be living in a double-wide down in South Texas,
or be pushing up some kind of perennial plant like Rainbow Knockout Roses.?.
What do you think? Too pink?