We recently had to replace our outside A/C unit. After 18 years it gave up the ghost (on the one weekend we had company!) After several frantic and pleading phone calls we had several people come out to give us quotes. Needless to say after hearing 4 figures I was in a panic. We were told by several different places that since we had an older unit we needed to move to a 410A (new refrigerant) and we would have to replace the entire system inside and out. I don't know about you but I didn't have an extra 7300.00 in the cookie jar to whip out and both DH and I had about thrown in the towel when along came our Knight in Shinning A/C. This honest AND helpful A/C specialist informed us that NO we did not have to replace the entire unit that our newer (2001) inside unit could be converted to handle the 410A with a simple valve change! This cut down our cost by more than double...so for 2300.00 we received a new 4 ton 15 Seers (sp) Carrier unit, new slab, new heavy duty hypo filter, new digital thermostat and the inside unit converted with a new valve and new relay.
Sooo if you have to get a new unit do the research to see if your inside system can be converted, saves tons of $$.