Maybe I am missing something or my casual test was a bit haphazard but I was underwhelmed. Just for the fun of it a few years back I did a before and after amp draw test on a new installation. I replaced one of those condensing units that was like an upside down U with the double shaft fan. Maybe a York? It was the type that took forever to dry out to check pressures after you washed it out. They also were sold under anther name as DIY units. I'll venture a guess that maybe it would have been equal to 8 or 9 SEER.
Anyway I replaced this 5 ton system, TXV coil (13 SEER) and the furnace. When all was said and done my TD was within a degree or so of the old system and the running amp draw was about one whopping amp less. That is the same as one average light bulb!
To sum it up, ever since that installation I have been very hesitant to make much of a point about how much more efficient new systems are or how they will pay for themselves. There are nowhere near enough cooling days in the Chicago area to justify that as reason alone.
I am curious about thoughts on this. The power consumption change was almost meaningless as far as payback time. So what am I missing?