<human>: Can you condense the text into three sentences or less?

I bought a home in December 2015 (live in OHIO if that matters). The home was purchased and flipped by the seller. I had general inspection, mold inspection, radon inspection and wood destroying insect inspection completed. I did NOT get the HVAC system inspected. The house has a heat pump (new installed in 2015). The air handler/furnace was not new and was 19 years old. I expected that I would have to replace that at some point. House has coverage under a home warranty. 

After receiving electric bills for $450 each (far more than expected for a house of this size) I had an energy audit completed. House has been air sealed and had insulation added. This did not bring down my bills. I then had 2 different HVAC companies come to check out the system and make sure it was working correctly. 

First guy was sent by home warranty people. He said that the pressure was off (sorry I don't understand how any of this works- all magic to me) and that it was caused by an obstruction at the time of installation. Due to this the home warranty people have denied my claim. I called a second guy for a second opinion. He said there is no obstruction but that the people had installed "the wrong kind of heat pump which does not match the furnace" and that the system has "two different kinds of refrigerant." He further explained that in doing so they have ruined the new heat pump and that will also need to be replaced now at a cost of ~$8K.

My questions is this: do I have any recourse to get the seller and/or installer to fix this on their own dime? My thinking is that once I signed off on the house it was mine along with any issues or preexisting problems which were not detected at the time of purchase. However, I have zero understanding of any of this and am wondering if I should seek legal advice.
<bot>: Bought house- seller incorrectly installed new heat pump last year- heat pump ruined due to this and now will cost me $8K to replace everything. Can I go after the seller?