There are many ways to choose a company to install your new air conditioning system. Here are some of the things I would recommend checking:
You will want to make sure that the company you choose is licensed and insured to perform the air conditioning installation. Many of the companies out there claim they are "licensed and insured" but I always like to see proof in writing. The reason the company needs to be properly licensed is because this allows them to pull the necessary permits and have the inspections completed by the city or township. It also shows that the company has the required training and experience to obtain the licensing, which means your job will be done to the code requirements.
Make sure that the contractor is properly insured to perform your air conditioner installation; you'll want to make sure that the air conditioning contractor carries a liability policy and also a workman's compensation policy on his employees. This protects you the homeowner if something is to happen to your home or one of the contractors employees is hurt while installing you air conditioning system. I always want to see this in writing. If the contractor is not insured and something happens it can come back to your homeowners insurance or you personally.
Also, ask a few questions about the companies hiring and screening process of their employees. You'll want to look for a company that does background checks and drug screenings on their people. I like to have an idea of what type of people will be coming out to my house. There are many contractors out there that have no hiring policies in place. It makes you think about who you would allow in your home. Do not forget to ask the contractor for referrals of customers where they have done a similar air conditioning job. Make sure to get the phone number and call their customer. Ask the testimonial a few questions to get a feel for the contractor that will be installing your air conditioning system and what you can expect from the contractor. I would recommend going and looking at the quality of workmanship if possible.
I also would recommend visiting the Better Business Bureau website. They have made it extremely easy to check on any contractor by just typing in their company phone number. If they are members you see the company's history, complaints, if any and how the complaints were resolved. This tells you a lot about how a company does business. This may not seem like an important thing to check but always check that the company actually has a real physical address and preferably an office at that location. There are many contractors who use post office boxes as their office. Where do you go if you do have a problem after the installation of your air conditioner? They are no where to be found. You will also want to look at the company's years in business; this usually lets you know you are dealing with a company that has a reputation to protect. In this day and age the company should have a website for customers to gather information and learn more about them. You should consider this when making your choice.
The last piece of information you will need to make an informed decision and pull everything together would be checking on their office staff, how the records of your air conditioner installation are recorded and maintained if they are needed in the future. How many service technicians do they employ in the event you need your system serviced in the future or a warranty issue arises? You can see that all of these things lead to the old saying "You get what you pay for". If you are getting pricing on a new air conditioning system, think about all of the above reasons why that other contractor is cheaper. Is he really cheaper in the long run? Check as many of the items above as possible before making your final decision.