My AC wouldn't work, and I called one of the big-name HVAC companies that advertises a lot on the radio. They arrived quickly, and found a 'major' problem. Their solution would cost about $8,000 but they could get started the next day if I agreed right then. Fortunately, I got a referral to Keuhn's from a friend, and got a second opinion. I didn't tell them what the first company suggested, and Keuhn's suggested a much more practical repair for 15% of the price. Two years later, still working fine. Its nice to find a contractor to trust, who doesn't make you feel like they are just trying to see how big of a bill you will tolerate.