MERV (Minimum Efficiency Reporting Value) is the standard rating system for air filter effectiveness, developed by ASHRAE. MERV ratings range from 1 to 16 for residential/commercial filters (with HEPA filters rated separately), with higher numbers indicating better particle capture.
MERV 1-4: Basic fiberglass filters, capture large dust particles only. MERV 8: Standard pleated filters, capture mold spores, dust mite debris, and pet dander — appropriate for most homes. MERV 11-13: High-performance filters, capture fine particles including smoke and some bacteria, recommended for allergy sufferers. MERV 13+: Hospital-grade filtration.
Important: higher MERV ratings restrict airflow more significantly. Using a MERV 13+ filter in a system designed for MERV 8 can reduce airflow, decrease efficiency, and damage equipment. Always verify your HVAC system can handle higher MERV filters before upgrading.