We make the Aprilaire filter part of most installs we do. This is because of the simple design, nothing to ware out. And unlike 1 inch filters, the Aprilaire filter does not sacrifice air flow but 1 inch air filters do because of there minimal service area for the air to travel through. Their filters have a whole line of filtration depending on how clean you want your air. Review the video to see how easy it is to replace the filter (about every 6 months).