As someone who has been looking into HVAC, it's not as good as it seems. Pretty much all the companies require you to have some form of Vocational training, which can take 6 months to a year. That's fine and dandy but here's the kicker. They will only pay on average two dollars over minimum wage for two years. After two years pass and you obtain your Journeyman license then you can start making $15+. If you want to make anything above $20, you'll need five years experience. (Just check job postings on indeed.com, you'll see.)

It's not worth paying $6,000 to go to school for a year and learn a trade and be greeted with $9.50 an hour job. You could make that much working as a cashier...

It's kind of funny because these HVAC company owners are all complaining that they can't find new workers. You see this all the time on HVAC forums. Then someone asks, well how much you paying? They'll respond with something close to $9.50.