How do I determine which filter to buy for my particular model of furnace?
Check your furnace's manual or the label on your existing filter for the correct size and MERV rating, then choose a filter that fits your system's airflow requirements — a technician can recommend the best option for your equipment.
Written by Paul Coen, Owner
How do I determine which filter to buy for my furnace?
Check your furnace's manual or the label printed on the edge of your existing filter for the correct dimensions and MERV rating, then buy a replacement that matches both. If you don't have the manual handy, the old filter itself is usually the fastest reference — most have the size stamped directly on the frame.
What information you need
Two specs matter most: the physical size (length, width, and depth, usually printed as something like 16x25x1) and the MERV rating your system can handle without restricting airflow. Buying by size alone without checking the MERV limit can lead to a filter that's too dense for your blower.
Where to find this information
- The frame of your current filter, usually printed along one edge
- Your furnace or air handler's owner's manual
- The manufacturer's spec sheet, often available from the equipment maker's website
If you can't find the size or aren't sure what MERV rating is safe for your system, our technicians can check it and recommend the right filter during your next visit — call LJ Refrigeration Co. at (480) 948-5004.