Check out everyone that provides you with a proposal with your local Better Business Bureau. They will have a rating for most contractors. You can’t rely solely on this information, but include it in your evaluation.
Check every contractor out with the California State Contractors License Board. www.cslb.ca.gov. Do this online, as it is difficult to get information from them by phone. They will provide you information about the company such as; If their insurance policies are up-to-date; Who really owns the company; Are their salespeople registered; and other pertinent information.
Make sure that everything that you have discussed with the salesperson is written in the contract, and don’t sign anything until you are completely convinced that everything is spelled out – in detail.
Ask questions like: What will happen if…..? How will you be doing …..? What exactly is the warranty? Do you use subcontractors to do the work? Will you be obtaining permits? What about duct testing?
Don’t take anything for granted. Better contractors will gladly tell you everything about their work. They want you to know all about what they’ll be doing and they’ll not hide anything from you.
Ask to visit one of their current projects going on. You’ll then see how their employees conduct themselves and if the customer is happy with their work.
Let’s face it, you’ll be spending a lot of money with someone. For your long-term benefit, be certain that you’ve selected them based on factors other than the cheapest price.