How to Change Your HVAC Air Filter — The Complete Guide

Changing your HVAC air filter is the single most impactful maintenance task a homeowner can do themselves. A clean filter keeps your system efficient, extends equipment life, and maintains indoor air quality. Here's exactly how to do it correctly.

How Often Should You Change the Filter?

The answer depends on filter thickness and your home's conditions:

• 1-inch fiberglass filters: Every 30 days
• 1-inch pleated filters: Every 60-90 days
• 3-4 inch media filters: Every 6-12 months
• 5-inch media filters: Every 9-12 months

Homes with pets, smokers, or allergy sufferers should replace filters more frequently.

Choosing the Right MERV Rating

MERV (Minimum Efficiency Reporting Value) measures how fine a filter's mesh is. Higher MERV = more particles captured. But there's a trade-off: higher MERV also means more airflow resistance, which can strain your blower motor.

• MERV 1-4: Basic fiberglass — captures large debris only. Not recommended.
• MERV 8: Standard pleated filter — captures dust, pollen, mold spores. Good baseline.
• MERV 11: Better pleated filter — adds pet dander, fine dust. Good for most homes.
• MERV 13: High-efficiency pleated — captures fine particles including some bacteria. Use only if your system can handle the resistance.

Do not install a MERV 16 or higher "HEPA-equivalent" filter in a standard residential system without consulting an HVAC professional — it will likely damage your equipment.

Step-by-Step: Changing a 1-Inch Filter

1. Turn off the HVAC system at the thermostat.
2. Locate the filter slot — usually at the air handler (indoor unit) or in a return air grille.
3. Note the size printed on the old filter's frame (e.g., 16x25x1).
4. Slide out the old filter carefully to avoid releasing trapped dust.
5. Place the old filter in a plastic bag before disposal.
6. Insert the new filter with the arrow pointing toward the air handler (in the direction of airflow).
7. Make sure the filter sits flush with no gaps around the edges.
8. Mark the date of replacement on the filter frame with a marker.
9. Turn the system back on.

Common Mistakes

• Installing the filter backward (arrow points away from airflow)
• Using a filter that's slightly smaller and leaves gaps around the edges
• Installing a filter with too high a MERV rating for your system
• Forgetting to change it — set a recurring phone reminder

Questions about what filter is right for your system? Call (435) 244-1090 and we'll point you in the right direction — no service call required.