Aprilaire Filter Replacement MERV 8 Foam Core and Aluminum Frame For Use With: 1830 1850 and 1850W Dehumidifier • The filter requires annual cleaning or replacement • It is constructed of metal with a foam core • Filtering most allergens the MERV 8 filter is able to trap particles as small as 3 microns • Filter should be cleaned or replaced once a year • The 5443 filter can be easily cleaned by simply flushing it with warm water and a detergent solution