These aren't just words to us at A-1 Furnace & Duct Cleaning LLC, they are the foundation on which our business is based. We are one of the true industry pioneers, who have actually been cleaning furnaces and ductwork since 1981, only one other company can make that claim in southeast michigan.. State-Of-The-Art Cleaning Equipment, Cleaning Furnace & Ductwork Systems, State of the Art Cleaning Equipment, Furnaces