I just purchased a home with a 1.5 year old dual Lennox heat pump system (upstairs and downstairs). I'm not sure the most efficient way to run this for each season; for example in the winter should I mostly run the lower unit and let the heat rise (which keeps the whole house warm), or mostly the upper unit and stay in the upper section of the house (I work from home and am home all day)?
I'd also like to install setback thermostats, the existing ones are simple digital controls. Can anyone suggest a good 2 zone controller? I installed one in my previous house 11 years ago, it had a simple daily / weekend schedule - have they gotten "smarter" lately?
Thirdly, is it worth my time investigating a GWHP or GLHP replacement for this system? Would I just be replacing the compressors or are they so radically different they are a total system swap?