We've used Filtrete filters for many, many years. Our 1991 90% efficient furnace is still happy and running strong  thanks to these great filters which protect it. We run the furnace November thru May. We use the Allergen Defense Filter 1000 for Nov thru December, and then in the following hi-pollen months,  we use the Filtrete Healthy Living Filter 1500. These filters are well-made and easy to insert. Our air feels healthier and our allergies (and our dog's) are kept in check.