Furnace and A/C Filter Sizes
Make the switch to a brand that has been trusted since 1950. All filters are manufactured in the US by AAF Flanders, the largest air filter manufacturer in the country. AAF Flanders filters are selected for their quality and value by organizations that require the cleanest air possible, including NASA and hospitals. Not all filters are created equal.
Where is my filter located?
Your filter can be located anywhere between the furnace and the where warm or cool air enters the room. Common locations include inside the ductwork, behind vents or in the air handler itself.
What size filter do I need?
Most furnace filters have two sets of dimensions; nominal and actual. If you measure your filter and it's actually 15 1/2" x 24 3/4" x 3/4", you would round up and search based on the nominal dimensions of 16" x 25" x 1". If the nominal size isn't printed on your old filter just measure your filter width, length and thickness. Round up and you'll get the nominal size. We always recommend measuring your filter just to be sure.