6 Things Homeowners Miss When Ordering Custom Size Furnace Filters Homeowners often assume that every furnace slot is a neat 16x25x1, but that's not always the case. Sometimes, you might need high-quality, affordable custom size furnace filters to keep your home feeling pleasant. If you don't pay attention to this... 6 Things Homeowners Miss When Ordering Custom Size Furnace Filters Homeowners often assume that every furnace slot is a neat 16x25x1, but that's not always the case. Sometimes, you might need high-quality, affordable custom size furnace filters to keep your home feeling pleasant. If you don't pay attention to this...