Duane Carlson, our Service Technician, was on time and fully prepared to do the work on our heating system. He identified the problem immediately and advised us as to the problem, the solution, and the cost of repairs. Repairs were made and tested. The furnace and work area were left clean and all debris was removed. We couldn't ask for better service. Sierra Air has been our HVAC service for nearly 15 years and has resolved every problem efficiently and cost effectively. We wouldn't use anyone else.