We called Air Tech about an air balancing problem.  We had 2 rooms that were too cold in the winter and too warm in the summer.Mark from Air Tech called before coming out to our house and showed up on time - actually he was early which was great. I explained the problem and he investigated.  He found that the damper on the air duct that feeds the 2 rooms was almost shut.  He opened it and also tightened the damper so the air flow wouldn't cause it to shut on its own. I had looked for a damper previously but didn't know what to look for. Mark showed me how to find the dampers and how to adjust them. He also gave us some useful tips.  Mark did the work fast, was friendly and did just what was needed. No b.s. The next time I need heating or A\C work, I'll be calling Air Tech.