Your HVAC (heating, ventilation, and air conditioning) system keeps your home's air clean by trapping dust, pollen, germs, and other contaminants, but all those particles have to go somewhere. The system's air filter collects much of this buildup, which can eventually start to interfere with the unit's efficiency, increase your utility bills, and even compromise your home's air quality. Learning how to clean an air conditioner filter or furnace filter is a key part of regular maintenance that can keep the system running smoothly and ward off a costly breakdown.
However, cleaning your home's air filters will only get you so far. If the filter is excessively dirty, torn, or otherwise damaged, it's time to replace your air filter. You should also note that disposable air filters (which are typically set in a cardboard frame) are generally not meant to be cleaned and should be replaced when they become dirty. Cleaning works best with reusable filters, like this washable electrostatic furnace and AC filter ($24, Lowe's).
How to Clean an HVAC Air Filter
For best results, plan to clean your home's air filters about once a month and replace them about every six months. Be sure to check the manufacturer's instructions to determine the best way to clean your air conditioner or furnace filter, but the steps below will work for most reusable filters.
What You Need
Vacuum with soft brush attachment
Large bucket or sink
Distilled white vinegar
Step 1: Turn off the power and locate the filter.
Before you begin, turn off your HVAC unit to prevent unfiltered air from circulating around your home while cleaning. Locate the vent and use a screwdriver to open the unit. Some systems might include multiple vents that each contain a filter, so be sure to clean them all. Remove the filter and inspect it for damage. Replace the filter if necessary; otherwise, continue on to vacuuming.
Step 2: Vacuum the air filter.
Take the filter outside if possible to avoid stirring up dust inside your home. Use a vacuum with a soft brush attachment to remove debris from the filter. Run the brush across the filter to gently loosen stuck-on buildup.
Step 3: Wash the filter with vinegar and water.
If your air filter requires deeper cleaning, fill your sink or a large bucket with a mixture of equal parts hot water and distilled white vinegar. Let the filter soak for approximately one hour, then rinse with clean water. If the filter is too large to fit inside a sink or bucket, use a garden hose to wash it off, letting the water run through the filter in the opposite direction of the airflow. Use a low-pressure setting to avoid damaging the filter.
Step 4: Let dry and replace.
Let the filter air-dry completely before replacing it. This helps prevent mold growth within your HVAC system. Reload the filter inside the unit, ensuring it's facing the right direction for proper airflow. Most filters feature arrow markings that indicate the correct placement; these arrows should typically point toward the furnace in the direction of the airflow. Replace the vents and turn the unit back on.