Air Purifier vs. Air Filter: What’s the Difference?

Air purifiers and air filters share a similar goal: they both capture or neutralize harmful contaminants to clean inside air. Many people use the phrase “air purifier” as an umbrella term to refer to any device that removes airborne contaminants. In that sense, an air filter is a type of air purifier.

However, air quality professionals often distinguish between the terms because the two systems are built differently and designed to remove different contaminants.

In this blog, we’ll answer the following questions:

• How does an air filter work, and what contaminants does it remove?
• How does an air purifier work, and what contaminants does it remove?
• Do you need both an air filter and an air purifier?

Want an air filter or air purifier recommendation from a pro? Call Four Seasons at 503-538-1950 today. Our trusted air quality specialists can help you find the right purifier for your home based on your family’s air quality needs.

An air filter refers to the filtration device built into your home’s central HVAC system.

The main job of the air filter is to catch large, airborne particles before they reach your AC or furnace, keeping your equipment free of debris and dirt buildup, which helps your HVAC system run efficiently.

Besides keeping your HVAC system clean, an air filter can also help purify your home’s air by removing large particles such as:

• Dust mites
• Pollen
• Mold spores
• Carpet fibers
• Lint

After a month or two, the particles we listed above will start to clog the filer. Regularly replacing the filter helps your HVAC system run efficiently and keeps those particles from circulating in your home’s air.

Yes, you can. We’ll explain...

A MERV (Minimum Efficiency Reporting Value) rating measures the effectiveness of an air filter. Filters with higher MERV ratings can capture smaller particles, and therefore do a better job keeping your home’s air clean.

Most standard air filters have a 3 to 8 MERV rating. These filters can capture the larger pollutants listed above but not smaller particles. The EPA currently requires that builders implement filters with a MERV rating of at least 8, ideally 13. Air filters rated over 9 MERV can capture additional pollutants such as:

• Legionella (a type of bacteria that causes lung infections and flu-like illnesses)
• Lead, cement, and humidifier dust
• Other particles that are as small as 1.0 micron (for reference, the diameter of a human hair is around 80-100 microns)

MERV 13 to 16 filters are capable of filtering even smaller particles, including:

• Pet dander
• Tobacco smoke
• Nuclei from sneezes
• Bacteria
• Particles as small as 0.03 micron (with ~75% accuracy)

The most effective residential air filters are called HEPA (High-Efficiency Particulate Air) filters. A HEPA filter has a MERV rating of 17 to 20, and it is capable of filtering airborne particles that are 0.3 microns or larger with 99.97%+ accuracy. Because they are so effective, HEPA air filters are often used in hospitals to stop the spread of airborne germs.

You can typically buy a MERV 8 to 16 air filter at your local home improvement store. Keep in mind that the higher the MERV rating, the more expensive the filter will be.

To install a HEPA air filter, you’ll want to contact a professional to do so for you. Because of the filter's size, it might need some modifications to your HVAC system for a proper installation, which a technician can complete.

An air purifier is a device designed to remove or neutralize harmful contaminants that a standard air filter cannot.

The most common kinds of whole-home air purifiers include:

• UV light air purifiers
• Ionic air purifiers
• UV/catalyst ionizing hybrid air purifiers

Let’s take a closer look at each of these kinds of purifiers and what pollutants they remove.

A UV light air purifier is a device typically installed in your HVAC system's air handler (also known as the indoor unit). It uses powerful UV-C light to neutralize harmful microbial matter, such as mold spores and bacteria, that commonly form on the coils of your AC system.

You can install an ionic air purifier near the blower assembly of your HVAC system to remove viruses, bacteria, and pollen from the air.

The ionizer sends out negatively charged ions into the surrounding air, which bond to positively charged airborne particles that pass by. Once the particles bond, they become heavy and fall onto a plate in the purifier, where they remain until cleaned off.

You can learn more information about air purifiers in our article, “How Effective Are Air Purifiers? A Portland Tech Explains”

A UV/catalyst ionizing air purifier is a hybrid of the two purifiers we discussed above.

One example of this kind of air purifier is the REME HALO® purifier. A technician will install this hybrid purifier in the supply side of the ductwork. It purifies air by emitting low-level hydrogen peroxide, which reduces up to 99% of the bacteria, viruses, odors, and mold in a home.

The REME HALO® purifier also pairs well with a solid air filter. The low-level hydrogen peroxide forces smaller airborne particles to clump together, which helps the air filter catch more particles.

An air quality expert can help you choose the best kind of air purifier for your home and HVAC system.

Sadly, Portland’s air quality isn't excellent. Because of this, more and more people are looking to keep their homes free of outside air pollution.

An excellent first step is to invest in an air filter with a mid-to-high MERV rating. Having a more effective air filter will improve your home's air quality—especially if you've only used standard air filters.

If someone in your home suffers from allergies, is sick often, or is sensitive to air pollution, and/or you’re concerned about the effects of wildfire smoke, we recommend pairing the high-MERV air filter with an air purifier. This stack will protect your loved one from even the smallest of allergy agitators and significantly improve the overall quality of your home's air.

Call Four Seasons at 503-538-1950 today. We can help you find the right air purifier/filter based on your family’s health needs and your budget.

When working with us, learn more about what to expect by visiting our air filter and air purifier service pages.