Complete Guide to HVAC Air Filters: Types, Ratings, and Replacement

Published: November 10, 2024 | 8 min read

Your HVAC filter is the first line of defense for indoor air quality and system protection. Understanding filter types, ratings, and maintenance ensures optimal performance and healthy air.

Filter Types Explained

Fiberglass Filters: Basic, affordable, MERV 1-4
Pleated Filters: Better filtration, MERV 5-13
Electrostatic Filters: Washable, uses static charge
HEPA Filters: Hospital-grade, MERV 17-20
UV Filters: Kills bacteria and viruses

Understanding MERV Ratings

MERV 1-4: Basic dust and lint filtration
MERV 5-8: Mold spores, dust mites, pet dander
MERV 9-12: Fine dust, bacteria, some viruses
MERV 13-16: Smoke, microscopic allergens

Replacement Schedule

Fiberglass filters: Every 30 days
Pleated filters: Every 60-90 days
Pets in home: Reduce interval by half
Allergies/asthma: Monthly replacement
Vacation homes: Check before each visit

Choosing the Right Filter

Balance filtration needs with system capacity. Higher MERV ratings provide better filtration but can restrict airflow in older systems. Most homes benefit from MERV 8-11 filters.

Filter Maintenance Tips

Set monthly reminders to check filters
Buy filters in bulk for convenience
Write installation date on filter frame
Check filter direction arrows
Never run system without a filter