locally pittsburgh window and door have a repair service.

remove section in trouble like 1/2 a double hung or picture window,
with frame intact.

they in a matter of ours disassemble the frame, measure and make a new
sealed unit.

our dogs throw themselves at our 3 foot by 4 foot picture window, it
fogged.

75 bucks replaced the sealed unit with warranty.

compare to 6 or 7 hundred quote for a new window, a local contractor
doing job at neighbor quoted me........