Oreck XL21 Upright Exhaust Motor Filter, 4-Pack

Part EF4PK is Oreck's exhaust motor filter for the XL21 upright, sold as a set of four. It filters the air coming off the motor right before that air leaves the housing, which makes it the last thing between the motor's own dust and the room being cleaned.

An exhaust motor filter earns its keep out of sight, which is why a clogged one costs more than suction. Restricted airflow at the motor raises operating temperature, and a motor that runs hot consistently wears out sooner than one that breathes freely, so the price of leaving a loaded filter in place is paid by the machine rather than felt at the nozzle. Buying four at once means the next one is already on the shelf when it is due, which is usually the difference between a filter that gets changed and one that gets knocked out and put back.

• Part: EF4PK, four exhaust motor filters
• Fits: Oreck XL21, XL21-450ECB, XL21-600, XL21-600ECB, XL21-600ECC, XL21-700, XL21-700ECB, XL21-700ECC, XL21-700ECP, XL21-750, XL21-750ECT, XL7-605EYB, and XL7-705ECB
• Change interval: on a set schedule rather than by appearance, since an exhaust filter gives little visual warning

Because this filter sits away from the obvious dirt path, it is the one owners forget entirely. Tie the check to something already on a schedule, a belt or brush roll inspection for instance, rather than waiting for a smell or a drop in pickup to prompt the swap. Open the housing fully each time and confirm the old filter came out in one piece, since a fragment left behind will sit against the fresh one and block part of it. Note the date on the box of spares as each is used, and the interval stops being guesswork on the next change.