Well, upon further research, I find that the 157% claimed is achieved at 77*F ODT with 86*F water out. Uh hello, I don't NEED to be heating when it's 77 out! And I need 140*F water out. They ARE playing with the numbers a bit.
So, according to their chart, at 45*F ODT with 140*F water outlet the efficiency rating is,,,
ODT*F %EFF
59 142
50 137
45 131
35 119
19 111
14 105
5 100
-4 96
(ODT= Outdoor Temperature)
Or is it they're like shooters. Showing you the good targets but not the bad ones.
LOL...
Still, the numbers don't look that bad.
Anyhoo, their "efficiency rating" means that at 100% you are spending the same energy to heat your house with the heat pump as if you were burning gas.
Another term for it is COP (Coefficient of Performance). The point at which you are getting out the same energy as you are putting in. According to the chart for the application I'm looking at 5*F is my COP with this unit
A conventional HP has a much higher COP. Let's say ~ 35*ODT for a rough number. Each application has it's own unique COP unless you put identical equipment in identical houses.