7 Types of Air Filters Explained – Choose the Best One for Your Home

If you’re looking to replace your air conditioner filters, then you must be shocked to learn how many different air filter types are out there!

This discovery can be pretty overwhelming, especially if you’re new to the world of HVAC systems. But fret not! This guide covers everything there is to know about the different types of AC filters for your home.

What Does the Air Filter In Your HVAC System Do?

The primary function of HVAC air filters is to remove harmful particles from the air as it flows through the system. This filtration ensures your indoor air quality is up to standard. Hence, they are an important component of your air conditioner.

What Is MERV Rating?

To measure filter efficiency, experts use the Minimum Efficiency Reporting Value (MERV). MERV is a rating scale that evaluates filters based on their ability to capture particles. The rating ranges from 1 to 16, with 16 awarded to air filter types with the highest filtration performance. MERV ratings vary by filter type and manufacturer. It is always mentioned on the package.

That said, opting for the highest MERV rating isn’t always the wisest decision. These filters are costly, and more filtering can lead to higher airflow resistance. This resistance places strain on your HVAC unit and reduces its efficiency over time.

Most residential HVAC systems are equipped with a MERV 8 filter by default. Upgrading to the recommended MERV 13-rated filter will remove viruses along with other contaminants. Thus, leading to better indoor air quality. As noted above, consult an HVAC professional to determine whether your system can handle a MERV 13 filter.

7 Main Air Filter Types

The primary difference between air filter types is their ability to remove various air-borne pollutants present in your home. This ability depends on the type and layout of the materials used. For example, a tightly woven, layered material will filter better than a thinner material.

So, to choose the most suitable HVAC filter type for your home, you need to understand how well each type of filter material performs.  

There are seven basic types of AC filters, each with its own advantages and disadvantages. Here is a list of all the kinds with their respective MERV rating.

1. Fiberglass Air Filters

Also known as flat-paneled or spun-glass filters, these filters consist of strands of glass spun together and reinforced with a metal grate. These are quite common due to their affordability. However, they don’t significantly improve indoor air quality. Fiberglass filters can only remove about 20% of particles that are around 3.0 – 10.0 microns in size. This includes lint and large dust particles. While this may help protect your HVAC system, they don’t provide effective air filtration.

MERV Rating: 1-4

• Pros: Spun-glass filters are the least expensive option. They are suitable for those looking only to keep debris out of their homes, such as lint or dust.
• Cons: Since these filters can’t capture smaller particles, they aren’t good at purifying the air. They can also become easily clogged and require monthly replacement. 

2. Pleated Filters

Pleated filters consist of a fabric medium made of either polyester or cotton. The material is folded to increase the filter’s surface area. These filters are slightly more expensive than fiberglass filters. But they are also more effective against contaminants. They even capture smaller air pollutants such as pollen, pet dander, dust mites, and mold spores.

Disposable pleated filters are made of polyester or cotton and primarily used in residential HVAC systems. They cost around $5, but need frequent replacement, sometimes monthly, to prevent system clogging. They have a MERV rating of 6. 

Permanent pleated filters provide excellent air filtration, capturing small particles easily, and usually have a MERV rating of 14–16. They are made of thick cotton attached to a sturdy metal frame. These filters don’t need frequent replacement, but they are quite costly. Commonly used in hospitals, but it can also be used in homes if someone has asthma or any other respiratory condition. 

MERV Rating: 6-16 

• Pros: The pleats increase the surface area of these filters, providing effective filtration capability. 
• Cons: Permanent pleated filters are more expensive than some other AC filter types. Filters with more pleats might also restrict airflow.

3. HEPA Filters

High-efficiency particulate air (HEPA) filters are one of the most efficient HVAC filter types. They can remove up to 99.97% of the air-borne pollutants and allergens present in your home, including dust, mold, pollen, pet dander, viruses, smoke particles, and bacteria.

They are far more efficient than typical residential filters, and their filtering capacity exceeds the standard MERV scale. However, if they were to be rated on that scale, they would correspond to approximately an MERV rating of 17–20.

MERV Rating: 17-20

• Pros: HEPA filters are highly effective against both large and small pollutant particles. Since the filters only need replacement every few years, they’re cost-effective over the long term.
• Cons: These filters are significantly more expensive than other types of air filters. Additionally, their high filtration efficiency may restrict airflow, reducing your HVAC system’s efficiency.

4. Washable Filters

Washable HVAC air filters are available in flat-paneled and pleated forms. They can filter out dust, pollen, common household odors, and some bacteria. They cost more than disposable filters do, but will save you more in the long run. Also, they are more environmentally friendly than their disposable counterparts.

To clean these filters, vacuum or rinse them to remove dirt and impurities. It is essential to ensure the filters are fully dry before reinstalling them. Using damp filters can lead to mold and bacterial growth, reducing indoor air quality.

MERV Rating: 8

• Pros: Washable filters are cost-effective and eco-friendly, and do a good job of filtering out common household pollutants. 
• Cons: These filters require regular maintenance to remain effective.

6. Electrostatic Filters 

Electrostatic air filters use self-charging electrostatic cotton or paper fibers to attract and trap dust, hair, and other small airborne particles. They are available as disposable or washable units. 

MERV Rating: 8-10

Pros: Washable filters can be reused, saving money over time. 

Cons: Require high maintenance and cannot filter out gases or odors. 

5. UV Light Filters

Short-wave UV light filters kill bacteria and viruses. The germicidal radiation from the UV lamp in these filters disinfects the air as it passes through. These are also effective at removing harmful microorganisms, such as mold spores, from your space. Because they focus on sanitization rather than filtration, UV filters are not rated on the MERV scale. 

UV filters do have some downsides. First, they could potentially convert oxygen molecules into ozone molecules. At low concentrations, ozone can cause minor health effects, such as coughing and chest pain. In higher doses, it can exacerbate asthma and other respiratory diseases.

Secondly, while UV light filters remove bacteria and viruses from the air, they are ineffective against pollutants such as dust. As a result, these filters are typically part of a more advanced filtration system, such as a HEPA filter.

• Pros: UV light filters get rid of disease-causing germs and pollutants present inside your home.
• Cons: These filters are ineffective against pollutants and allergens, including dust, smoke, and fumes. They are also more expensive than other air filter types.

Related: What Are HVAC UV Lights For?

7. Electronic Filters 

They are high-efficiency filters installed in the ductwork. These filters use a high-voltage charge to ionize particles and collect them on oppositely charged plates. They’re permanent, washable, and effective at trapping allergens, dust, smoke, and pet dander.

Pros: They are reusable and are highly effective at capturing fine smoke particles. 

Cons: They are quite expensive and may produce traces of ozone, which is a lung irritant. 

How to Choose Between Different Air Filter Types?

There are several factors to consider when choosing among AC filter types.

For example, people with allergies, asthma, or other pulmonary diseases should get filters with a higher MERV rating. Also, if you have pets, live with smokers, or often leave your doors and windows open, a higher-rated filter would be a better fit.

But people who don’t prioritize superior air quality, clean living environments, or debris blocking can buy lower-rated, cheaper filters. Filters with very high MERV ratings are suitable for hospitals, smoking lounges, and care units for the sick.  

Summing It Up

Choosing among the various HVAC air filter types can be confusing. The market is flooded with AC filters with various functionalities. It’s essential to keep your home’s requirements and MERV recommendations in mind.

For instance, if your home’s occupants have allergies, select a filter with a higher MERV rating. However, since not all systems support these filters, it’s essential to check compatibility in advance. Installing a filter with a MERV rating that’s too high will cause strain on your unit. An excess of which can lower your unit’s lifespan and long-term efficiency.

As a general rule, it is recommended to clean your AC filters every 250 hours of operation. While this cleaning is essential, it can often slip through the cracks on your to-do list. We recommend using smart thermostats or smart AC controllers that send reminders when the next cleaning is due.

We hope you won’t be confused by the many HVAC filter types and can make a smarter choice for your system!