I am new to the forum. I wanted to ask a question. I came across an ad for a used trane xl1800 unit (Model TTZ060A) its a 5 ton unit with a Trane air handler TWE065E13. Its a used unit and the person selling it wants around $ for both. I currently have a rheem 4 ton unit that is 12 seers and the unit is about 14 yrs old now (1996 RBEA model). My unit runs good but it doesn't have anything like a variable speed system or like a 2 stage compressor or anything. I was wondering if I buy this Trane and get it installed for maybe total price $ ( installed). You guys think its worth in helping saving money on electric bill? (my electric bill has been past 3 months over $350) ( Oh sorry I didn't mention I just bought my first house in miami fl so this is for my new home) Or better off waiting for the a/c unit to die and then get something? I was thinking its so cheap I can probably get that money back in less then 2 yr. The guy is selling the unit b/c he's taking it out of a foreclosed home. My home is a 2200 sqft home.