How to Pick the Best Air Filter for Your AC Unit

When the temperature climbs and that air conditioning unit kicks on, most people only think about the relief of cool air. But an AC unit is just like any other appliance in a home. It requires regular maintenance and basic upkeep to be safe, efficient, and effective. Homeowners can take control by making sure to frequently replace the air filter for their AC unit and selecting one that is the best fit for their needs.

Start With the Current Filter

To see if the current filter is the best type for you, remove it from the AC unit, take it outside along with some regular table salt, and hold the filter horizontally. Take the salt and pour it over the filter, noting how much comes out of the bottom side. If salt falls through the filter, it will let dust, hair, and other debris in through the AC unit. 

This can be especially concerning when a home has pets or people who suffer from allergies. Even smokers can negatively impact the air quality in a home if the filter isn’t manufactured to stop contaminated air from going through.

Some homeowners may find that filters are in difficult places to reach and may need to contact an air conditioning company to come help with filter replacement and preventative maintenance. 

Filter Size Matters

If a person buys shoes that aren’t the right size, there can be all kinds of problems when they try to walk in them. The same concept applies to the size of the filter being used in an AC unit. 

Look at the existing filter for accurate measurements or measure the space itself. Many AC units have space for standard filters, but others require a different size. An AC unit with the correct sized filter will significantly impact overall air quality.

Not All Filters are Created Equal

One of the most important things a person should understand about AC unit filters is their minimum efficiency reporting value, also known as MERV. MERV indicates how efficient a filter is at its job. Keep in mind that the highest MERV-rated filters can be expensive in the long run as an AC unit has to work harder to pass air through a finer filter.

Consider the differences between filters as you shop. Fiberglass filters are common and tend to be affordable but need to be replaced frequently. Pleated filters tend to be a little more expensive than fiberglass, but they can trap more allergens.

For anyone conscientious about their impact on the planet, look into washable air filters. They do not trap allergens like other filters, but their ecological footprint is minimal. Disposable filters may be a better option to trap allergens, though it is not as eco-friendly.

Consider what particles are most commonly trapped by different MERV ratings. For ratings 1 through 6, these filters have been shown to trap particles like dust mites, pollen, and small fibers. Ratings 8 through 13 can trap dust mites, smog, smoke, and mold. Ratings 14 through 20 can trap odors, bacteria, and viruses. Choose what’s best suited for your needs and budget.


Any home can improve its air quality with the right filter. However, some feel overwhelmed and unsure about which filter would be best for their needs. It never hurts to contact an HVAC professional to find the right filter. A quick assessment and recommendation can be all a person needs to enjoy exceptionally clean air in their home.