This fiberglass filter is one of the strongest panel filters made. For the best results, change this filter every 30 days. s   s This synthetic filter offers higher efficiency filtration due to its special pleated design and will easily last 60 days in most homes. This cotton-polyester filter exceeds industry standards for pleated panel filters. Often used in healthcare facilities, its 70% efficiency will dramatically improve your indoor air quality and should be changed every 90 days. s This synthetic, electrostatically charged filter, our most efficient, highest quality filter, is designed to trap the smallest of airborne particles including mold, bacteria, smoke, and pet dander.