Here in Tucson, we have had an average high temperature of about 105 degrees over the past week. It's hot. Really hot. So a well functioning AC unit is essential during this time of the year. But what if your AC unit is noisy? You may be comfortable in your home, but now you have to deal with a whistling, thumping, or other distracting noise. So today we're talking about AC units and the noises they make - what's normal, what's fixable, and when you should call in a trade pro to take a look a...