Step 1: Locate your furnace or HVAC unit in your home (call mom, dad, or grandpa if you need help)
Step 2: On the side of your current filter, you should see numbers that translate to width x length x depth (note these - you'll need them for the Fit Guide).
Step 3: If your filter doesn't show the size, find a tape measure (very helpful) and measure the width, length, and depth (write that down).
Step 4: If you're still having trouble, contact our customer support team (last resort, but we're here to help).
Step 5: Now that you have all the info you need... Have another go at the Fit Guide!