Premium H13 True HEPA Material: This Honeywell HEPA filter replacement, the HPA300 filter, is made from premium HEPA 13 / MERV 17 material to dramatically improve the quality of your home. It is best to change the filter regularly: In order to maintain the best filtration performance of your machine, we recommend replacing it every 6 months. At the same time, vacuuming the outside of the filter every 30 days, or helping to remove some of the dirt outside the filter, can also extend the overall life of the filter.