Lot of talk on this forum about which AC is best.  I have a General Electric three and a half ton unit installed in 1979 when I build the house, and also a 100,000 BTU gas furnace.   It is not the most efficient, 8 SEER,  but it has been bullet-proff; I have never spent a penny on service or had to put any feron in.  It is quiet and keeps my 2,100 s.f. house comfortable in 100+ weather.    I have hosed the condensing unit off, that's about all.  Unfortunately, GE got out of the central AC business years ago.  I have been told that Trane took over and have heard good things about Trane, but they are expensive.

I've decided to keep this system and ride it out, trying to see if I can get 40 years out of it.  You can't justify trading cars just to get better gas milage.  Can you afford to scrap a good heating/AC system for a higher efficiency?