I have owned my present home since 1975. During the past 40 years I have installed two new furnace/AC,units. Over the years I have tried several different brands of filters. Once I found the Filtrete brand, I never used anything else. I change the filters on a regular basis and have always been totally happy with the results. I normally use the Filtrete 1000 filter that I buy locally. You make an excellent product that does a great job in helping keep my house and furnace clean. Congratulation on making such a fantastic product.