There are a lot of professions that the person must have a school degree plus state certifications. Many certifications are noticed across the nation & occasionally in other countries. The Heating & Air Conditioning industry can be much more difficult that other card holding jobs. Very few trades require more than 1 certification or license. In the Heating & Air Conditioning world, most people have to have a few cards. Union members may have to possess a worker’s card, but it can be even more difficult for a Heating & Air Conditioning person to just bounce around every few years. During my research into Heating & Air Conditioning employment demand I found out some cities require many different kinds of licensing. You could possibly be required to hold a propane license, steam license, boiler license, oil boiler license, and/or refrigeration license. The environmental laws can vary state to state & a newly elected politician can literally stop the clocks of an entire sector if he/she chooses to do so. Depending on their sense of urgency with the climate change, common requirements can change. A few states require electrical & plumbing licensing to work in Heating & Air Conditioning. Contractors have just as much difficulty to go through before they can start working, especially in crucial southern states. The list of state supplier licenses across the United States is astounding, with the list of needs being almost the same difficulty. When an individual wants to work on furnaces, cooling systems, & water heaters, she or she may want to look into local requirements and the price of obtaining those prerequisites.