Wow, Yesterday I had my 23 year old Rheem SEER 10 replaced with a new Trane XR15 4ton Condenser unit and matching GAM....... air handler (matched certified system SEER of 16.25) The old Rheem just was not able to keep up on the hot days, and my Summer electric bills were over $800 per 2 month billing period. I certainly did not do the replacement to save money, as I doubt the new system will last as long as the old Rheem, but, man, does this thing cool the house down, and dehumidify it well. They also installed an Aprilaire MERV13 air cleaner. The manual J they did showed another 1/2 ton was appropriate for my house than the 3 1/2 ton unit I had before. And the install qualifies for a power company rebate of 700 bucks. Anyway, I imagine my electric bills will be reduced by one third in the Summer; we'll see. The attic temps yesterday were 145 degrees on the sheathing and the air temp up there was about 130 degrees. Brutal on the installing crew untill they had the system running and provided themselves with some cool air up there while they connected up the rooms. I was up there every so often for maybe 10 minutes or less at a time, and I don't know how they do it, I really don't. I gave them a nice tip for their hard work. Oh yeah, AHHHHHHHHHH again!