Furnace maintenance in Buford, Georgia. Two systems. Changed filters. Tested mechanical and electrical components. Found upstairs system with no water safety, dirty blower wheel, badly worn igniter, and worn flame safety sensor. Found downstairs system with badly worn igniter, worn flame safety sensor, and dirty blower wheel. Due to age and condition of furnaces, recommend upgrading them to more reliable, more efficient furnaces. Systems are heating at this time.