Different Types of Air Filters and How They Work

Maintaining indoor air quality is something that every homeowner worries about, especially if a family member has asthma or other respiratory issues. The right HVAC air filter can turn stuffy, contaminated air into clean and fresh air. 

If you’ve never replaced or installed an air filter for your HVAC system, it’s better to learn the different types on the market. While HEPA filters remain the most popular, there are various other options that may be a better fit for your home and AC system. 

Keep reading to learn about the seven different types of air filters and how they work. 

Pleated Filters

Pleated filters are made with cotton folds and polyester fabrics, with a MERV rating somewhere between 5 and 13. These filters are good at filtering dust and most airborne pollutants, but they deliver low air filtration. 

The pleated build of these filters increases the surface area, allowing for better filtering and giving them an advantage over non-pleated filters. The more pleats an HVAC filter has, the better it can trap mold spores, pet dander, difficult allergens, and other pollutants. 

You can also find disposable and reusable versions of pleated filters, which may dampen the whirring noise of your HVAC fan. However, it’s worth noting that pleated filters make your HVAC system work a little harder than it should. 

They provide some restrictions in pulling the room’s air through the unit, which can raise your utility bills or cause premature failure in your HVAC system. Still, they’re an affordable option to get the job done if you’re not up for a splurge.

Read More : Fiberglass vs Pleated Air Filters

Spun Glass Filters

Spun glass filters are made with multiple strands of fiberglass spun together in an intricate pattern. These are one of the most common picks when it comes to HVAC filters, as they’re disposable and affordable. 

Plus, they protect your furnaces and air conditioners from circulating debris. Spun glass filters are known for their efficiency, and a high-end version would be an ideal fit for a modern air purifier. 

However, these filters can only catch some allergens and dust and may not drastically improve the air quality in your home. So, if you’re living with someone who has respiratory problems, spun glass filters may not be the right pick.

Media Filters

When choosing between media filters and standard filters with higher MERV ratings, it may seem obvious to pick the latter option. However, media filters may have certain benefits to consider, as they can deliver the same air filtration as a filter with a higher MERV rating. 

Plus, they’re affordable and don’t have the downside of static pressure or restricted airflow. Instead, their surface area allows them to prevent static pressure and provide better air filtration. Media filters are also great at filtering bacteria and are relatively easy to maintain. 

You’ll only need to change them once or twice a year, so they’re a great pick for someone with a busy schedule. 

Washable Filters

You may find certain air filter types in disposable and reusable forms, but washable filters will always be the better investment. Not only do they cost less in the longer run, but they’re also environmentally friendly, helping you overlook the initially high price. 

In order for them to work well, you’ll need to follow the maintenance instructions while washing them. Also, it’s crucial to dry them completely before putting them back in, as wet air filters can cause long-term issues like mold or HVAC system failure. 

Unfortunately, washable filters typically have low MERV ratings, but they’re still a worthwhile investment if you’re a beginner and not too picky about your filters.

Electrostatic Filters

Electrostatic air filters are made with small paper and cotton fibers to create enough static to serve as a magnet for airborne particles and pathogens. This electrostatic magnet is strong enough to keep the particles stuck to the filter until you replace it. 

If your family members have allergies, electrostatic filters may be the ideal pick for your home. Additionally, you can find electrostatic filters in disposable or reusable forms, so you can save money on replacing them too often. 

UV Filters

True to their name, UV filters rely on short-wave ultraviolet light to kill all bacteria and viruses that enter the surface area. The HVAC unit extracts the air while the UV lamps kill all pollutants with a process called germicidal radiation. 

If you’re concerned about mold growth in your home, UV filters may be the ideal option for your HVAC system, as they can kill hazardous microorganisms. However, it’s worth noting that some UV filters may convert oxygen into ozone by breaking down the air atoms. 

Even a small intake of ozone can lead to chest pain and coughing, while a higher intake can worsen a pre-existing respiratory disease, such as asthma. Plus, these filters aren’t too good at getting rid of airborne pollutants, such as dust, but they are better at killing viruses and bacteria. 

That’s why UV filters are often used alongside HEPA filters in a larger filtration system. The light bulbs for UV filters must also be replaced annually, depending on the HVAC system. 

Read More : Benefits of Air Filter

HEPA Filters

Lastly, High-Efficiency Particulate Air (HEPA) filters are the most common filter type used in household HVAC systems due to their efficiency and affordability. In fact, the US Department of Health recommends these filters due to their ability to remove 99.97% of airborne pollutants and allergens. 

That includes dust, mold spores, and other particles smaller than 0.3 microns. Plus, these filters have a MERV rating of 16, so you can count on them to maintain the air quality of your home. HEPA filters can also remove tobacco particles and bacteria, making them ideal for those with asthma. 

If you or your family members have allergies, HEPA filters are the ideal pick for your HVAC system. You’ll need to replace them once a year and consult a contractor to install them professionally.


Understanding the different types of air filters you can fit in your HVAC system is the first step to improving your home’s air quality. HEPA filters are the most common option in this application, but each filter type has its pros and cons to consider before purchase. If you’re not sure which one is best for you, consult your HVAC technician for guidance.