Air Purifier vs. Air Filter: Which is Best for You?

  • By: Sue Dorrens
  • Date: February 22, 2022
  • Time to read: 7 min.
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There are all types of devices that help clean the air of contaminants so that breathing in fresh air is a lot easier but when it comes to an air purifier vs. air filter, which one is right for you? Numerous studies have proven that the average home has five times the pollutants inside than are found outside, so the problem is very real. This article is here to help you answer that question.

Basic Differences Between Air Purifier and Air Filter

An air filter is built-in to your central air (HVAC) system and filters airborne particles, but an air purifier is a stand-alone device that can be purchased for those who want cleaner and safer air.

When people say “air filter,” they’re talking about the air-filtration device that is built into your home’s central air conditioning system. Most people change this filter once a month, and there are many different types of air filters to choose from.

The main job of your HVAC filter is to catch large airborne particles before they get to your AC or furnace. This keeps the equipment free of dirt and debris and also helps your HVAC system run more efficiently, saving you some money on your utility bill in the meantime.

Some of the particles the filter removes include:

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

On the other hand, air purifiers not only trap these pollutants but work to eliminate them as well. The best air purifiers use a true HEPA filter that zaps all sorts of pollutants, including very small pollutants that may in fact get past the air filter in your AC unit.

There are air purifiers you place on a tabletop or shelf, and there are air purifiers that you can install in your HVAC system.

Some of the latter can be installed by the homeowner, whereas others have to be installed by an HVAC professional. An air filter should be replaced monthly because, after about a month, the pollutants start to clog up the filter. Air purifiers work a little differently.

To sum up, an air filter is part of your HVAC system, and there are types of air purifiers that you can install in your system. An air filter traps large particles and keeps them there so they don’t reach the AC unit or furnace, whereas air purifiers, which can be whole-home or simply sit on a tabletop, both trap and eliminate the pollutants so that you don’t have to deal with them anymore.

The efficiency of both the filter and the purifier depends on how it’s manufactured and what type of actual filter it is. Both filters and purifiers come in various types to allow you to decide which one is best for you.

Check out our article on Best Woodshop Air Filtration System: Our Five Picks.

Types of Air Filters

When it comes to air filters, there are many different types. HVAC air filters are given a MERV rating, which stands for minimum efficiency reporting value, and a standard air filter has a MERV rating of 3 to 8. The larger the number, the smaller the particles the filter can capture. Currently, the EPA requires builders to use filters with a MERV rating of at least 8, preferably higher. Air filters with a MERV rating of 13 are considered industrial strength and are preferred by many homeowners.

In fact, if you get an air filter with a MERV rating of 9 or higher, it can get rid of much smaller pollutants such as:

  • Lead dust
  • Cement dust
  • Legionella
  • Humidifier dust

In addition, filters with MERV ratings of 13 to 16 can get rid of even smaller pollutants, including:

  • Tobacco smoke
  • Pet dander
  • Bacteria
  • Nuclei from sneezes

Once an air filter’s MERV ratings get up to 17 to 20, it is known as a HEPA filter, and by law, all HEPA filters must meet certain requirements. First of all, HEPA filters must filter airborne particles that are as small as 0.3 microns in size. Second, they must do this with 99.97% accuracy or higher. This is why places such as hospitals typically use HEPA filters since they do such a great job of getting rid of even the smallest contaminated particles in the air.

If you choose to buy an air filter with a MERV rating of 8 to 16, you can usually find them at your local home-improvement store. Naturally, the higher the MERV number, the more expensive the filter will be.

If you choose instead a HEPA air filter, it’s best to contact a professional to install it for you. Why? Because HEPA filters are large and you may need some modifications to your HVAC system in order for it to fit properly. For the right technician, this task is super simple.

In addition to MERV-rated and HEPA filters, there are other types of air filters available for your home, and they include:

  • Fiberglass filters. These are very common disposable filters that trap the pollutants in layers of fiberglass. Some of these filters are electrostatically charged so they can catch larger numbers of particles
  • Activated carbon filters. Usually used as pre-filters or secondary filters, activated carbon filters are very porous and therefore great at trapping all types of pollutants in the air. They work wonders when it comes to reducing certain odors.
  • Washable filters. These filters tend to be very cost-effective because you simply wash them under cool water then let them air dry before using them again.

Types of Air Purifiers

We’ve already mentioned that air purifiers not only grab hold of certain contaminants but also neutralize or remove them so they are no longer there. This is something a standard air filter cannot do. You can choose a portable air purifier that sits on your tabletop or shelf, or you can choose a whole-home air purifier and the latter works in one of three ways.

The first one is a UV light air purifier, which is installed in the air handler, or indoor unit, of your HVAC system. This type uses UV-C light, which is very powerful, to neutralize contaminants such as bacteria and mold spores, which often form on your AC system’s coils.

Air Purifiers

The second type of whole-home air purifier is an ionic one. This one is usually installed near the blower assembly of the HVAC system in your home, and it removes bacteria, pollen, and viruses from the air. The purifier sends out negatively charged ions into the air, which then bond to positively charged particles or contaminants. After this happens, the particles become heavy and fall onto a plate located in the purifier. They remain on that plate until you clean it off at a later time.

Finally, there are the UV/catalyst ionizing hybrid air purifiers, which basically combine the features of the two air purifiers we’ve already mentioned. These air purifiers emit low-level hydrogen peroxide, which reduces up to 99% of contaminants such as mold, bacteria, odors, and viruses.

The Reme Halo air purifier is an example of this type of purifier. If you pair this type of air purifier with a solid air filter, you’ll get the best contaminant removal possible. The low-level hydrogen peroxide in these purifiers causes smaller airborne particles to clump together, and the filter is able to catch even more of them.

Should You Get Both an Air Filter and an Air Purifier?

Since air filters catch pollutants so they don’t go any further and air purifiers both catch and eliminate them, it’s not a bad idea to have both an air filter and an air purifier in your home. If you have allergies, asthma, or other upper-respiratory problems, it’s a good idea to have both, but if you do not suffer from any breathing problems, a high-quality air filter is likely all you need.

Try to get a filter that has a high MERV rating so that even more pollutants will be captured and prevented from going into the air. Does this mean that you’ll be paying more for these filters? Of course, but they’re always worth it in the end.

Keep in mind that as a general rule, air filters will trap only large contaminants, while air purifiers trap and eliminate both large and small ones. Things such as pet dander are very small, so only a good air purifier will trap the smaller pollutants.

Air purifiers are also great at removing numerous volatile organic compounds, or VOCs, which include harmful things such as formaldehyde. Purifiers can trap contaminants down to 0.3 microns in size, which is roughly the size of 1/200 of a strand of hair. This is yet another reason why both air filters and air purifiers are recommended for most homeowners.

Final Thoughts

Both air filters and air purifiers have their advantages, but if you want the most protection possible against all types of pollutants, you need both.

This is especially true if you have any type of breathing issues. They also come in a variety of price ranges, so you should have no trouble finding products that you can afford.

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