The person from Hartz Heating & Cooling Inc who came out to my home knew his stuff extremely well, and he explained everything very carefully. This was my first time using them, and I had them come out to do a full service on my heating system. He cleaned it up, tuned it up, and he was a pleasant person the whole way through. Even when I called for the first time to set my appointment, the people over the phone were extremely friendly and flexible with what I needed. I will absolutely use them again.