PureFilters 4 Inch
PureFilters house-brand pleated 4 inch furnace filters, most offered in MERV 8, MERV 11 or MERV 13. Popular sizes such as 16x25x4, 20x25x4, 20x20x4 and 24x24x4 come in 3-packs; less common sizes such as 16x22x4 and 25x29x4 come in 6-packs. Match the size printed on your current filter.
See all PureFilters furnace filters or every 4 inch furnace filter we carry.
PureFilters 4 inch filter guide: size, MERV and replacement ▾
Finding your size
Use the nominal size printed on the frame of your current filter, such as 16x25x4. The actual size is usually a little smaller; our guide to nominal vs actual filter sizes explains the difference. 3-packs cover common sizes like 16x20x4, 16x24x4, 18x24x4, 20x24x4 and 12x24x4. Less common sizes, from 8x16x4 to 28x30x4, come in 6-packs; see custom size furnace filters if yours is not listed. We also list PureFilters replacements for Honeywell FC100A1029 (16x25x4) and FC100A1011 (20x20x4) media filters.
Which MERV rating?
MERV 8 captures dust, lint and larger particles. MERV 11 filters also catch finer particles such as pet dander and pollen, and MERV 13 filters capture finer particles still. A higher MERV can restrict airflow in some systems, so check your furnace manual if you are unsure.
How often to replace
A 4 inch filter usually lasts longer than a 1 inch filter, often about 6 months. Check it every couple of months and replace it sooner if it looks dirty or you have pets.
