Completed furnace, maintenance and inspection. I checked all amp draws and components. I cleaned flame sensor and wiped down furnace. I tested airflow and temp splits. The filter that was in the filter slot when I arrived as a very restrictive filter which was causing the air pressure on the furnace to be higher than we would typically like to see. We switched out the restrictive filter and put the electrostatic filter back in. Airflow pressure was better with that filter than the allergenic filter. Furnace is operating within manufacturer specifications at departure. Customer would like a new box of electric static filters. We will order them and have them delivered to the home.