MERV 8, 11 or 13? Picking a home air filter without killing your airflow
Anjali Rao · 7 min read · 17 Aug 2026
A higher MERV number is not automatically better. Here is how to match a home HVAC or purifier filter to your system and your city air.
MERV is the rating scale for how much your filter captures. Higher numbers capture smaller particles — and restrict more airflow.
MERV 8 — basic dust and lint. Fine if your only goal is protecting the blower.
MERV 11 — pollen, mould spores, pet dander. A good default for most Indian homes.
MERV 13 — PM2.5, smoke, bacteria carriers. What you want in Delhi NCR from October to January.
Going above MERV 13 on a residential ducted system usually costs you more in airflow than it gains you in air quality. If you need better than that, add a standalone purifier with a true H13 HEPA cartridge instead of forcing your HVAC to do it.
For split ACs there is no MERV rating — the stock mesh is a dust screen, not a filter. A cut-to-fit carbon sheet over the mesh is the practical upgrade.
Replace pleated home filters every 3 months, or every 2 months during smog season.