Commercial vs. Residential and Schools
Of course, schooling varies with the area but in the States can be found at trade schools or through community colleges or magnet programs within the high school system. Some of the magnetic schools teach night classes at a fraction the cost of trade schools and are just as effective when finding a job.
In Canada, BCIT, NAIT, SAIT are some of the best in BC or Alberta. Honeywell Building Solutions is always hiring good HVAC mechanics and instrumentation techs. Many times the person will benefit from further training while on the job.
Commercial work is probably more dependable for a steady paycheck. Residential service providers may be have more peaks and valleys to the work. When people are having financial struggles they may not have the money to fix what needs to be fixed.