There is a large flat 5 by 2 foot painted metal panel with lower air vents. Turn 45 degrees the two screws at top (you will needn#4 Allen wrench; turn 45 degrees and lift off panel. You will see air filter. These filters are an odd dimension: 16.25 inches X 26.75 inches X 1 inch thick. Install with arrow on label pointing to furnace, as that is the direction of air flow. Williams Oil Filter Service Company at 1247 Puyallup Avenue has stocked these air filters for the Esplanade. Some residents buy an upgraded 20 X 30 filter at most hardware stores; and then shape to fit. Tip: Cut label off old filter and take with you to purchase replacements. Several things can shut down your air handler besides the thermostat—Like a clogged water condensation hose. Get help or advice from building maintenance.