When choosing a replacement, matching your system dimensions is essential. Check the nominal measurements on your current frame and choose an efficiency rating suited for your system.
Parts with these numbers
20" x 25" x 4" MERV 8 Multi-Pleated Panel Filter (Hart & Cooley 102700030)
20" X 25" Media Air Filter (Honeywell Home FC100A1037)
- Length x width: match the size on the frame
- Depth: must match the slot: 1, 2, 4 or 5 in
- MERV: pick what your system can handle
Understanding 20x25x4 Filter Sizing
The numbers printed on the filter frame represent its nominal size in inches. Nominal dimensions are rounded numbers used across the industry. For example, a filter labeled 16x25x1 really measures about 15.5 x 24.5 x 0.75 in. This slight difference is completely normal and allows the frame to slide in and out of the housing without jamming.
A 20x25x4 filter requires a dedicated 4 in slot. Never force a 4 in filter into a 1 in or 2 in track, as bending the frame damages the seal and crushes the pleats.
Reading the Label and Airflow Direction
To find your filter specifications, look at the outer cardboard edge of your current filter. The outer edge displays the nominal length, width, and thickness. It also lists the MERV rating, which indicates how fine the filtration media is.
The frame also includes an airflow arrow. When sliding the filter into place, make sure this arrow points toward the furnace or air handler and away from the return duct.
Comparing 20x25x4 Options
Different 20x25x4 filters offer distinct features and efficiency levels. Both options listed share the 20" x 25" x 4" nominal size but use different designs.
The Hart & Cooley 102700030 is a pleated panel filter made from synthetic material with a MERV 8 rating. The Honeywell Home FC100A1037 is a media air filter rated at MERV 11, and it replaces part number CF100A1025. Many homes use MERV 8 to 11. While higher MERV ratings catch smaller particles, they can also slow airflow on some systems.
Signs Your Filter Needs Replacement
A clogged filter restricts air circulation throughout your home. When airflow drops, your blower motor works harder, and you may notice weaker airflow coming from your supply vents.
Inspect the pleated surface regularly. A heavy buildup of gray dust or visible debris across the pleats means it is time for a fresh filter.
How to confirm it fits
- Turn off power to the unit at the breaker before opening the filter access door.
- Remove the current filter and read the nominal size printed on the outer frame edge.
- Verify the frame reads 20" x 25" x 4" to match your length, width, and depth.
- Check that your equipment filter rack is built for a 4 in depth rather than a 1 in, 2 in, or 5 in slot.
- Select a MERV rating your system can handle, such as MERV 8 or MERV 11.
- If your old Honeywell Home filter shows part number CF100A1025, choose the compatible FC100A1037 replacement.
Questions
Which way should the airflow arrow point?
The airflow arrow printed on the filter frame must always point toward the furnace or air handler, facing away from the return air duct.
What parts does the Honeywell Home FC100A1037 replace?
The Honeywell Home FC100A1037 replaces part number CF100A1025.
How do MERV 8 and MERV 11 filters differ?
MERV 8 and MERV 11 indicate filtration efficiency. The Hart & Cooley 102700030 provides MERV 8 filtration, while the Honeywell Home FC100A1037 provides MERV 11. Higher MERV ratings catch smaller particles, but they can slow airflow on some systems.
Can I put a 4 in filter into a 1 in slot?
No. Filter depth must match the equipment slot. A 1 in slot requires a 1 in filter, so never force a thicker filter into place.
Related guides
Brand names and part numbers are used only to show fit. HVAC Fitter is not affiliated with, authorized by, or endorsed by any equipment maker. If you are not sure a repair is safe for you, call a licensed HVAC technician.