In the Knoxville area, A-1 Certified Service, Inc. is well known for providing exceptional furnace repair, installation, and service. The people we send out to serve you are also top notch, something you'll see in their reviews below. Everyone you deal with at our company has the goal of making sure your experience with us will be so good you'll call us every time you need help. You can feel confident working with A-1 Certified Service, Inc. because we stand behind our work and comply with all local codes. This is why, as you can see by the map and reviews below, we are rated so highly for AC, Insulation, & Furnace Repair in Duff, TN. Call us today at (865) 691-5088!