I have an air flow part in my furnace that requires periodic cleaning. About a month after Alpine Climate Control, Inc. came out to address the issue, it clogged up again. They guarantee their work, so they sent out another service tech. The second service tech they sent was exceptional! He took the time to explain to me what was going on, and he showed me how to maintain the part myself. He did a wonderful job, and I am glad that I can now do this without having to call anyone out.