How to choose an HVAC air filter MERV rating

MERV (Minimum Efficiency Reporting Value) is a rating from ASHRAE Standard 52.2. It runs from 1 to 16; a higher number means the filter captures a larger share of small airborne particles.

1. Find your size first

The nominal size is printed on the frame of your current filter, for example 16x25x1 (width x height x depth, in inches). The actual dimensions are usually slightly smaller than the nominal size. Buy the same nominal size and depth your filter slot was designed for; a 4-inch media cabinet needs a 4-inch filter, not a 1-inch one.

2. Pick a MERV level your system can handle

• MERV 8: common general-purpose residential filter for dust and lint.
• MERV 11: finer filtration, often chosen for pets or allergies.
• MERV 13: higher efficiency for fine particles; the EPA suggests MERV 13 or the highest rating your system's fan and filter slot can accommodate.

Higher-MERV filters can add airflow resistance, especially in 1-inch slots. If your equipment manual lists a maximum filter rating or pressure drop, follow it. If you're not sure, ask your HVAC technician. Deeper 4-inch filters have more media area, which generally helps keep resistance lower at a given MERV.

3. Replace on schedule

Follow the filter and equipment maker's interval. 1-inch filters are typically replaced more often than 4-inch media filters; check the filter monthly and replace it sooner if it looks loaded with dust.

Examples from our catalog

• 3M Filtrete 600 Dust & Pollen Reduction Air Filter - 16x25x1 (4 Pack) — $60.37
• 16x25x1 Merv 11 Universal Air Filter By Tier1 (Single Filter) — $45.97
• 16x25x1 Merv 13 Universal Air Filter By Tier1 (Single Filter) — $53.74

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Related categories: HVAC Air Filters. General information only; follow the equipment maker's instructions and local codes. Updated 2026-11-14.