Those ads crack me up! I went to tech school for two years, believed all the crap that the instructors fed me, "After you're done with this program, you'll be able to work on anything." Maybe work on anytjing, just not fix anything.
The field is not like a laboratory setting, there are a lot of other variables- weather, complex control systems, irate customers. A solid HVAC education is good in that it provides you with a foundation from which to build your career. But there is no beating "The School of Hard Knocks".
Thirty days to cover the width and breadth of HVAC theory and practice seems ridiculously short. I don't know how they could successfully impart lasting knowledge in such a short period of time; especially to an individual with limited or no electromechanical experience. It makes no sense. Although I have seen residential HVAC companies in this area advertising the same thing- "30 Days to a New Career- Regardless of Background!" Once again, I don't know how they can do it. Maybe that's why so many companies are condemnning whole systems when there might be but a minor problem. I guess sales is what counts.
Seriously though, I would have grave reservations about such a short program, especially if you are really serious about becoming an HVAC tradesman.