If you are using a 1" thick pleated air filter you may be asking for trouble. Some homes were built with unsatisfactory ductwork. If you have undersized duct for the size of your furnace you may be compromizing the life of your heat exchanger by running these very restrictive filters. The higher the merv rating, the more restrictive your filter will be. If you need better filter performance do to allergies, do not buy these expensive 1" filters. Spend your money on a 4" wide media filter at the very least. These air filters provide much more filtering area and don't need to be changed for 6 months to a year. I have gotten customers air cleaner installation covered by medical insurance do to allergies. If you have allergies make sure you talk to your doctor about a prescription for an air cleaner.
If you insist on running a 1" filter then use a cheap fiberglass filter like the one below.