How to Change Your HVAC Filter — Complete Guide

Professional How to Change Your HVAC Filter — Complete Guide in Asheville & Western NC

Every HVAC System Has a Filter — Here's How to Find Yours

Whether you have a furnace, heat pump air handler, or packaged unit, there's a filter that needs regular changing. The location varies: horizontal air handlers (common in WNC attics and crawl spaces) typically have a filter slot on the side or bottom of the unit. Upflow furnaces have the filter at the bottom, near the return duct connection. Some homes have a filter grille in the wall or ceiling of a central hallway — this is your return air grille, and the filter slides in from the front. If you've never found your filter, check all of these locations.

Handling Different Filter Configurations

Some systems have multiple return vents, each with its own filter. If you have return grilles in several rooms, check each one for a filter. Others have a single large filter at the air handler and no filters at the returns. A few older installations have filters at both locations — the returns AND the air handler — which causes excessive airflow restriction. If you find filters in both places, remove the return vent filters and use only the air handler filter. Ask a technician to confirm the ideal setup during your next HVAC maintenance visit.

The Swap: Step by Step

Turn off the HVAC system before changing the filter (running it without a filter, even briefly, lets dust into the system). Remove the old filter and note the arrow on the frame showing airflow direction — it should point toward the air handler or furnace. Insert the new filter with the arrow matching this direction. If there's no arrow, the side with the wire reinforcement grid faces the air handler. Close the filter door or grille securely. Turn the system back on.

Setting a Maintenance Schedule That Sticks

The best filter-change schedule is one you actually follow. Set a phone reminder for the first of each month during the heating and cooling seasons. Stock up on filters — buy a 4-pack so you always have replacements on hand. For Asheville and WNC homeowners, April and October are good months to start fresh filters as you transition between heating and cooling seasons.