HVAC, which stands for "heating, ventilation, and air conditioning," is not a degree program one just jumps into one day and decides that this is his or her calling in life. Because HVAC training takes a minimum of two years to complete, it is something to which you must commit. This is especially true when you take into consideration the number of classroom hours and thousands of dollars required to enroll in a trade school program for an Associate's degree in this line of work. As if that were not enough, your school advisor will continually ask you every semester, "Where are you going with that [degree]?" You can give one of the following responses.
A person who chooses to solely work in the commercial sector of HVAC does so because he or she wants to work for city or state government and/or provide services for factories, office buildings, retail buildings, etc. Some HVAC technicians become contractors, working independently and securing work contracts for themselves. Other commercial HVACs work for an HVAC company that focuses on the commercial aspect of this line of work.
Refrigeration is a whole other side of HVAC. If you complete refrigeration certification, you are able to provide services to both residential and commercial customers for their refrigerators and walk-in coolers, respectively. It does not take much either, considering you already have to learn about refrigerants in your air conditioning classes and training. Most HVAC degree programs in trade schools give you the option of taking the extra classes for refrigeration certification as electives.
Simply put, you can tell your school advisor that you plan to work in the residential sector of HVAC. This means that you will only take "house calls." when customers call for service. You will not be taking any business from commercial consumers. While many people in your line of work would probably not choose to be so restrictive, it may just be that the hours are more attractive to you.
This is the equivalent to a doctor graduating as a general practitioner. You both just want to get your degrees and practice your careers in general. Neither of you are concerned about a specialty or focus. You get into a program, complete your studies, and get out of the program with a degree. For HVAC technicians, that can be advantageous from the standpoint that you can take any customer service call, anytime.