Elkhart handles heating and cooling work through its own licensing, not just a state card. The City of Elkhart says electrical, mechanical and plumbing permits must be obtained by a licensed contractor before work starts, and a Mechanical Contractor licence here means passing the ICC F29 National Standard Master Mechanical Exam or being reciprocated from another Indiana jurisdiction. The city does not accept reciprocations from other states. For you, that changes what to ask before a furnace, heat pump or air conditioner job in Elkhart, Goshen, Bristol or nearby. Ask whether the company holds a mechanical contractor licence with the City of Elkhart, not only one from somewhere else. Ask who will apply for the permit, and expect it to be in the contractor's name, applied for before work starts. If a frozen pipe or a burst line needs plumbing work, a Plumbing Contractor licence in the city starts with a State of Indiana plumbing licence, so ask to see that too. Get all of this written into the quote.