Tier One did excellent work for our neighbor and we experienced the same at our house. Service was at the promised time. Tier One inspected the work needed and had all parts available for the work day. The technicians were cheerful though they worked in our 100+ degree attic space. They were also as neat as possible, removing shoes at the door. Work was done according to estimate with no surprises. I would hire them again for any maintenance on my furnace or a/c