Arrived to do a performance maintenance. Set up for combustion analysis temperature split and static pressure tests. Verified operation of all mechanical and electronic components of the furnace. Checked blower for cleanliness and to see if there is any play in the bearings. Found that the fan for heating and cooling is coated in dust debris. Checked systems heat exchanger to ensure proper venting of flue gas. While checking the heat exchanger found that some dust debris had impacted on the evaporator coil. Considering the top of the line filter in the system and the dust found in the furnace and ac, checked the ductwork for cleanliness. Found heavy dust buildup present in the systems ductwork. Verified operation of the humidifier. Cleared the restriction in the humidifier feed line. Humidifier panel is coated in calcium and bacterial growth. Spoke with homeowner about the system. With homeowners approval replaced the furnace filter media and installed a new humidifier panel. Tested op