7 years is not old, 10 seer vs 14 is apx 37% more efficient. There are
units of 18 - 19 - and 20 seer plus. Depending on your climate you
should run the numbers for payback. There are air handlers with VS DC
motors that save 50 % of your electrical costs in winter, raise seer
by 1 and can dehumidify twice as much. You have more options then you
know .