I'm not saying that what you want is impossible, but I am struck by your overconfidence about it.

I think that overconfidence could be your undoing.

Now, if all you want to do is to go into people's homes and convince them that they need a new system, and use minimum wage workers to slap a system in while you regard yourself as a business owner, well, that is a model that many companies use. It is also one of the reasons that big box stores have gotten into HVAC sales.

Properly diagnosing and repairing a system is much more subtle AND challenging. If you had spent a few years here reading posts by guys who do this work, you would realize 1) how poorly the trade is taught in most places, and 2) how poorly the science is understood by many technicians.

While you and I are are possibly capable of the same choices of employment by background and education, I am the one who has been doing this work for many, many years, and I can tell you that your plan lacks that insight from experience. I think you are imagining that this is less challenging from a technical/customer service/management standpoint than it really is.

The bottom line is the type of company you are imagining. If you are imagining a conventional residential HVAC company, I hope you are the Ace of Sales. If that's the case, hire a service manger and couple of techs today, and forego the schooling entirely. Let them run the technical and you can get out the Big Rake.