Where does one make the choice to go 80% or 90%+ on
gas furnaces. I live in VA Beach, VA. I am about to replace 2 HVAC systems that are 19 years old. Over the last 10-years our winters have gotten colder. Having said this, our summers are also getting hotter with very high humidity so I am not sure what SEER rating I should be looking for. Would appreciate the help on both a furnace and a/c unit rating recommendation. My house is 2400 sq feet, 2-story and has a very open floor plan with 16 ft ceilings.