Choosing a replacement furnace filter might not sound like a difficult task, but when you look at the numerous options available, your decision may suddenly become surprisingly complex and confusing. The easiest choice is to get an exact replacement of what you already have. But is that costing you more... Choosing a replacement furnace filter might not sound like a difficult task, but when you look at the numerous options available, your decision may suddenly become surprisingly complex and confusing. The easiest choice is to get an exact replacement of what you already have. But is that costing you more...