After only a week, the Clean Filter light came on. The booklet said they should be cleaned weekly while other brands I've had in the past said monthly or as needed. Anyway, I took them out & they were not dirty so put them back in w/light still on. I will keep an eye on them. Just hope it lives up to the reputation of the brand name. In terms of effectiveness, it keeps a large room comfortable & is more quiet than other brands I've had in the past. Quite pleased.