'Most have a low end single speed 80% furnace with cheap low seer AC.
Then top line 93-94.5 % efficient furnaces with VS DC motors for more
comfort , humidity removal, lower electric usage and very high seer AC
units. It depends on where you live- your heating cooling needs and cash
you have. '

It also depends on how long you are planning on living in your home ;
Variable Speed DC motor furnaces will take a very long time to get a
payback on ; they get an arm and a leg for them . IF youre planning on
staying in the house for 20 plus years, then okay...otherwise, they are
only good to impress the Friday night Card Game regulars (if they are so
duped). Weigh up how much you run the Cooling...if you are not big a/c
buffs, then going with an extreme EER a/c unit is pointless due to a
long payback period. If you want to save a good 25% of the cost...go
with a Rheem, Goodman , or Tempstar brand over hyped up advertised
brands like Trane, Carrier, and Lennox. Each one of these brands will
last as long as the others so long as they are properly maintenanced.