Arrived to do a performance maintenance. Set up for combustion analysis and static pressure tests. Verified operation of all mechanical and electronic components in the furnace. Cleaned the flame sensor and retested its performance. Checked blower for cleanliness and to see if there is any play in the bearings. Found that the blower wheel is collecting dust and the ductwork is very dusty. Checked systems heat exchanger to ensure proper venting of flue gas. Checked for carbon monoxide in the air stream. Performed an electronic gas leak search. Spoke with homeowner about the system. Set up smart ac system and signed homeowner up for the maintenance plan. Furnace is functioning properly at this time.