30 models · 2 brands

HVAC & Furnace Filters: Home Air Quality Guide

A clogged furnace filter restricts airflow. ENERGY STAR — a US EPA and Department of Energy program — states that a dirty filter will slow down air flow and make the system work harder to keep you warm or cool, wasting energy. Its guidance: check the filter every month during heavy use months, change it if it looks dirty after a month, and change it at least every 3 months.

Jump to brand:Filtrete Honeywell

Brand · 15 listings

Filtrete

Brand · 15 listings

Honeywell

Reference · Buying Guide

How to Choose the Right HVAC/Furnace Filter

HVAC filters are rated on the MERV scale (Minimum Efficiency Reporting Value) from 1-16. MERV 8 captures common household dust, pollen, and mold. MERV 11 adds pet dander and smog particles. MERV 13 captures bacteria and smoke. For most homes, MERV 11 is the optimal balance of filtration and airflow.

Filter dimensions must be exact. Measure the width, height, and depth of your existing filter or check the size printed on its frame. Common residential sizes include 16x25x1, 20x20x1, and 20x25x4. Using an incorrect size allows unfiltered air to bypass the filter entirely.

The 1-inch vs. 4-inch debate: standard 1-inch filters are cheaper but need monthly replacement. 4-inch (or 5-inch) deep-pleated filters cost more upfront but last 6-12 months and provide better filtration with less airflow restriction. If your system supports a 4-inch filter housing, it's the better long-term investment.

Reference · FAQ

Frequently asked

01What MERV rating should I use?

MERV 11 is ideal for most homes. MERV 8 is adequate for homes without pets or allergy sufferers. MERV 13 is recommended for allergy-prone households or homes near construction. Do NOT use MERV 16+ in standard residential systems — the airflow restriction can damage your blower motor.

02Can a higher MERV filter damage my HVAC system?

Yes, if you exceed your system's rated capability. Higher MERV means denser filter media, which restricts airflow. Most residential systems handle up to MERV 13 safely. Check your HVAC manual or consult your technician before upgrading beyond MERV 11.

03Which direction does the filter go in?

The arrow on the filter frame points in the direction of airflow — toward the blower/furnace. For return air grilles, the arrow points toward the wall (into the duct). Getting this backward won't damage anything immediately but reduces filtration efficiency.

Federal Protection

The Magnuson-Moss Warranty Act (15 U.S.C. 2301-2312) prohibits manufacturers from voiding your warranty solely for using third-party replacement parts.Read more