Conditioned air needs can be divided into two categories: equipment servicing and equipment purchasing. When having equipment serviced, inquire about additional charges (such as travel charges) prior to servicing; ask if technicians are paid on an hourly or commissioned basis; consider annual servicing to prevent future problems.
When purchasing a new air system, be sure to get two or more bids. Make sure all bids are based on the same specifications; your local utility company can provide information on what capacity air conditioner you need for your home. Ask for local references and inspect finished work.