Research local HVAC contractors by calling the Better Business Bureau and inquiring about complaint records, how long contractors have been in business and owners. Look for contractors who have been in business for a long time without any serious customer complaints. Do not hire any contractor with a bad record with the Better Business Bureau. Once you have a short list of local contractors who've been in business a long time and have good records with the Better Business Bureau, open a file for each of the top three. Call and ask for customer references, contract, and financing policies.
Get a good understanding of your HVAC needs. If you are considering an installation of new equipment, research HVAC systems and equipment before making any final decisions. For existing systems, read your equipment manual, or request one from the manufacturer if you don't have it. Get a couple of books from the library about homeowner HVAC problems and troubleshooting, Know what kind of HVAC service you need before seeking a contractor.
Avoid making any quick decisions about contractors. Unless you have a true emergency, such as furnace failure during sub-zero temperatures, allow yourself time to research and question contractors before contracting for service. Obtain at least three estimates for the work -- especially replacement and installation, as well as references, before you make any decisions.
Ask for references from contractors you are considering and call them. Ask about their experience with the contractor in question, their satisfaction with the quality of the work and the price. Talk to friends, neighbors and acquaintances and ask if they have any experience with the contractors you are considering. Call your local building and zoning inspectors and ask them about their familiarity with the contractors in question.