My Carrier heat pump indoor coil heat exchanger had a leak so I had it replaced and while at it I had the heat pump replaced with a Hisense variable speed heat pump. This gave me a new 10 year warranty as my warranty of the system has expired. The HVAC firm that did it said that my Carrier Infinity Tstat and gas furnace are all compatible with the Hisense heat pump. Well, they were wrong about that. It didn't work so they added a Carrier NIM interface which they thought would fix the problem, but it doesn't. So, now they are trying to sell me on a universal Tstat. The dealer that I am dealing with does not have a contract with Carriier so they say they can't get a new Carrier heat pump. All this led me to researching universal Tstats. I've been using a Carrier Sam module interface which communicates with my home automation system through a serial connection. It has worked very well for many years. Carrier Infinity Tstats use a proprietary communication protocol which is not compatible with any other Tstats, so I have been told. The Venstar is attractive because it has a local API that can be used to interface it to a home automation system. According to ChatGPT the Hisense heat pump AUWR-60-U3SP2 can be controlled from a universal Tstat and the Carrier Infinity furnace can also be controlled from a universal Tstat except I would lose some features such as variable fan speed and some other features that I have yet to discover. So, it seems that this might be a solution, although not without losing some furnace features. Of course, ChatGPT could be wrong about this. I discovered that Hisense has a relationship with Johnson Controls. It looks like they are the creators of the Hisense HVAC controls. There is a Field Kit HMH7AK001 which I have been told by my dealer that it will work as an interface to the Carrier furnace so that with a universal non-communicating Hstat and the Hisense heat pump that it should all work together. I am concerned that my dealer might be wrong again. I am a retired electrical engineer and computer programmer, so I have some skill and a limited understanding about HVAC systems. I thought there might be someone here in this large forum that could chime in with an opinion.