I hate to disagree with everyone, but I have two Janitrol units install(Upstairs and downstairs) since 1985. I have had no service calls to date!!! However, I have begun investigating their replacement, since they are probably nearing the end of their life expectancy. Anyone use Rheem or Ruud, how about York systems? Carrier I've heard they have problems. Has anyone installed the high efficiency two stage gas furnances or the variable staged systems??? Remember I going to need two of them.