I was introduced to this trade by my older brother who had already been in the trade for several years prior to me in the state of Florida. One day we got together and just started working together. He was my first instructor and then I decided to enroll at The Refrigeration School here in Phoenix back in 1989.
We service, repair and replace heating and cooling equipment including hot water heaters.
One question I would ask someone like me who showed up at my door to "repair" my heating/cooling system would be, "How long have you been in the trade?" and "What did you do before you got into this trade?" Be cautious of the service tech with a lengthy sales background.