Heat recovery systems on air conditioners used to be quite popular here in Florida but you don't see many of them being installed these days. I've heard some A/C contractors make claims that they don't make sense anymore with the new more efficient equipment but I don't know if that is just uninformed talk.
I've personally put a kWh meter on a hot water heater that had such a system and I can verify that, over the several weeks time that I was testing it, the element came on very little. Of course, it only works when the A/C is running. Speaking of which, wouldn't it do just the opposite (cool your hot water) when used on a heat pump that is in heating mode, barring any control to prevent it from circulating in that mode?
It also seems like they would increase the efficiency of the A/C when they were running.
Bottom line, what are the issues with heat recovery systems on residential straight cool or heat pump systems? For any non-experts here, this is an example of what I am talking about.
Thanks for your input.