Furnace maintenance in Suwanee, Georgia. Two systems. Did not change filters, customer prefers to use more breathable filters and filters had recently been changed. Tested mechanical and electrical components, found no pressing concerns. Systems are 15 years old and may not last much longer though. Tested static pressure. Found downstairs system to have high static pressure , recommend installing additional 10†return and 8†supply for system. Recommend installing surge protection for furnaces to protect them from power surges. Systems are heating normal at this time.