Are you thinking about upgrading to a newer and higher 16, 18 or 20 SEER rated central air conditioner? I spent a lot of time comparing SEER and EER efficiency ratings and tried to determine how much money I would be saving in my electricity bill. I had such great electrical savings that I had to make a video showing how much you could save by putting in a new high efficiency A/C unit. 

http://quickandeasyhomeandgarden.blogspot.com/2015/09/new-air-conditioner-or-repair-you-choose.html