I replaced two 13,500 BTU's with two 15K's. one of them (Advent air, which for maintenance reasons I do NOT recommend) takes the exact same current, running, as the OEM, bit more starting,, The other (Coleman) takes 0.4 amps more The originals were Carrier AirV's
But at 10 years.. It depends on why it has failed, a New A/C, installed, is roughly 1,000 give or take a bit depending on where you do it.. Less if you DIY but I really don't recommend DIY as it's about 70-90 pounds you need to raise to the roof.. Within my capacity when I was 30, not so much today :).
On mine I have spare blower motors, fans, blowers, and such (For Carrier if you need one) even cowling.. But the cooling system,, Compressor, evap, condenser, dryer and piping and valves.. if that's shot, or dry (lost coolant) replacement is indicated in most cases.
