Definition
MERV (Minimum Efficiency Reporting Value) rates how effectively an air filter captures particles, on a scale from roughly 1 to 16 for residential use. A higher MERV traps smaller particles — dust, pollen, pet dander, smoke. But a filter that's too restrictive for your equipment chokes airflow and can strain the blower or freeze the coil.
Why this matters for your home
The best MERV is the highest one your system is designed to handle. Often the right answer is a deeper media filter cabinet that delivers high filtration with low resistance, rather than cramming a dense filter into a slot built for a thin one. Matching filter to equipment protects both your air and your furnace.