Thought I would post this image of our buffer tank over the last day, I am thinking we can point those who want to try a single tank setup to this image. As you can see the temperature rise or heat transfer really noses over the hotter the tank gets. Once over 120 the rise is almost nonexistent in our setup, of course when the tank gets down into the 70's the rise is really steep, although not shown in this graph. Our system is a 2 ton 2 stage setup, during this time we have run in 1st stage only. I am sure larger systems that have bigger exchangers in them will have a faster recovery, but I think the fall off would be very similar.