I'm using a TED unit on my two Sanyo ASHPs and it's not to bad..
I regret buying one with software, when the plain jane would have worked just as well, for my needs anyways...
It has two probes you snap over the 230vac pair, you want to monitor.
I've got mine looking at both of my Sanyos.
I use it to watch total power use, in case there's a problem and to know
what my monthly bill is going to be for heat..
You might want to use your monitor to check your hotwater heater first and then
move the probes to the GSHP afterwards.. Might be hard to do them simultaneously,
unless the wires off the breakers were right next to each other (and had some slack).