Currently have Lennox Complete Heat system installed 1998 still working knock wood. But, looking for replacement. Was going to go furnace and separate water heater. But, understand AO Smith Vertex and Polaris units can do hot water and forced air heating. So I am looking at these as possible replacment for the Complete Heat unit.

1) Any comments about either the Vertex or Polaris units from those who have installed them in hot water & heat applications.

2) Do you think I could use the air handler from the Lenox Complete Heat unit I currently have installed for heat?

3) Do I need a plumber for the water heater and an HV guy for the heat or is that usually done by the same person/company.

Appreciate any advice from the pros here before I start calling around.