I currently own a gas forced hot air 90 plus efficiency which is going on 20 years old. In November of 2014 I had the cicuit board replaced under a HVAC contract which covered all parts/labor. The unit has been running fine since then. I also have an outside AC unit (single stage)that is the same age and have replaced a capacitor once on it. I have noticed the last 2-3 years it has not removed the the humidity out of the house like it used to. I know that I want to replace the A/C unit this year. Where I’m hung up at is should I replace the furnace also to do it all at one time? By replacing them both I would consider a 2 stage A/C unit and acquire better humidity control. If I would only replace the AC unit to adapt to the current furnace, I would only be able to get a single stage AC unit. Are the 2stage AC units that much more efficient ? I live in Pennsylvania where I cool about 4.5 mtgs out of a year. Please provide me with your thoughts or guidance regarding this matter.