The most important aspect is the filtration method with mechanical filters being the most reliable choice. Additionally, you’ll want to think about how often the filters must be replaced as this represents a fixed cost that must be factored into your overall household budget.

Another nice-to-have feature that will impact your selection process includes finding an air purifier that is compatible with your room size. You’ll also want to think about the noise output as this can impact your willingness to have an air purifier in your bedroom. And finally, nice functions like remote control, or air quality sensor, can help to improve functionality. Keep reading our best air purifier buying guide to learn more.

Beginner’s Guide to the Best Air Purifier

What is an Air Purifier?

No matter how clean you keep your home, dust, allergens and other pollutants will find a way in. A good air purifier is ideal in helping to remove harmful particles from the air that might otherwise cause lingering odors or serve as irritants that can trigger allergies or asthma attacks.

While it is possible to have a built-in air purifying filtration as part of a home’s overall HVAC system, not everyone has access to this. A good alternative is to use an air purifier. Typically, air purifiers are designed to circulate and filter the air within a certain size range. Normally air purifiers are intended to filter the air in a single room, but it is possible to find models that can work with larger spaces.

How Air Purifiers Work

Not all air purifiers operate in the same way. Multiple technologies are available when you shop for an air purifier to filter the air in your home or office. Common options include mechanical filters, activated carbon filters, ozone generators, and electronic air purifiers, ultraviolet germicidal irradiation (UVGI), and photocatalytic oxidation.

Of the above options, mechanical filters tend to be the most popular options. Usually, they’ll contain a pleated filter made with a dense web of fibers and a fan. The fan forces air through the filter which forces particles to get trapped in the fibers. In some cases, this type of air purifier will feature HEPA filters which are considered incredibly effective at trapping particles as small as 0.3 micrometers in diameter. This includes smoke particles. However, you’ll usually need to replace the filter every six to 12 months — especially if you use the air purifier consistently.

Activated carbon filters are another popular option for people that are especially concerned with removing odors from the air. Because of the carbon composition, they’re ideal for getting some gases out of the air but aren’t very effective at removing particles. As a result, it’s not uncommon to see that this type of filter is often paired with a mechanical filter to improve efficacy. Still, activated carbon filters require more frequent replacement, as much as every three months.

Ozone generators and electronic air purifiers can be risky choices as both of these options create ozone as a byproduct of filtering the air. As a result, this can have the unintended effect of reducing air quality. According to the Food and Drug Administration (FDA), people shouldn’t be in environments with ozone levels above 0.05 parts per million. But many of these filters can produce ozone above those guidelines. This is especially problematic for people with breathing conditions such as asthma, bronchitis, or emphysema as ozone can make symptoms worse.

UVGI air purifiers are marketed to also kill bacteria, fungal spores, and airborne viruses thanks to the inclusion of UV lamps. But this claim is often debatable as to effectively kill pathogens, the UV light must stay on for minutes or hours. In contrast, purifiers with UV lights often only trigger the light for a few seconds.

Photocatalytic oxidation is often promoted as a way to remove volatile organic compounds (VOCs) through the use of UV radiation and a photocatalyst like titanium dioxide. Research has shown that the claims are dubious and the process doesn’t effectively remove VOCs. More importantly, just like with ozone generators and electronic air purifiers, there’s a higher risk of ozone being created as a byproduct.

Why You Should Buy an Air Purifier

Anyone who struggles with allergies, or just wants a home that smells fresh, will benefit from adding an air purifier to frequently used rooms. In most cases, everyone can use an air purifier. But if you’re still on the fence, check out the reasons below.

Are Air Purifiers Worth Buying?

You Want to Remove Lingering Odors: Sure, you can invest in air fresheners to keep your home smelling fresh. But those sprays are temporary at best. A good air purifier that includes a carbon filter can go a long way towards removing pesky odors — especially if you cook strong-smelling foods or recently painted something.

You Have Allergies or a Respiratory Condition: Thankfully most irritants that trigger allergies or respiratory events like asthma attacks are large enough to get caught in a mechanical filter. Even if you only want to minimize seasonal allergy symptoms, a good air purifier for dust is a smart investment that improves indoor air quality.

You Live in a Region with Known Poor Air Quality: On the whole, the United States as a nation has relatively good air quality. But there are pockets across the country that are known to have higher pollution levels. If you live in such a region, a good air purifier is a smart choice.

Why Air Purifiers May Not Be for You

You Dislike the Long-Term Financial Cost: Beyond the initial purchase, you need to consider that air purifiers have filters that must be replaced. While HEPA filters are more expensive than cheaper mechanical filters or even carbon filters, this represents a fixed cost that you’ll have to factor into your overall household expenses every three to six months at a minimum.

General Air Quality in Your Region is Fine: As we mentioned, on the whole, the U.S. has pretty good air quality. If you live in a part of the country with consistently good air quality, an air purifier might not be necessary.

You Dislike the Noise: Typically most air purifiers have multiple modes and are often promoted as quiet with low decibel output. But if you’re very sensitive to noise, you might find this appliance annoying even in the lowest setting.

You Don’t Understand That Air Purifiers Only Remove Small Particles from the Air: An air purifier, like the top air purifiers for babies, isn’t a solution to get rid of visible dust, dirt, pet dander, or larger allergens like dust mites that have already landed on surfaces including soft spaces. For this, you’ll need to buy a highly-rated air purifier for allergies and dust. But, if you’re buying an air purifier to get around dusting and vacuuming, you’re going to be disappointed.

How Long Will Air Purifiers Last?

The question isn’t how long the air purifier lasts, but how frequently you need to change the filter to maintain better air quality. Keep in mind that depending on the model you choose, you may need to change the filters more frequently unless you opt for a filterless air purifier.

Many air purifiers also feature a prefilter that you can manually clean. Periodically washing the prefilter can help to extend the life of the primary filter (carbon or HEPA) and stretch the timeline for replacing it.

Activated carbon air purifiers, like the leading ionic air purifiers, require that the filter be replaced every three to six months. In contrast, air purifiers with mechanical filters must be replaced every six to 12 months depending on your usage levels. Because air purifiers are intended to run continuously to ensure better air quality, this is a fixed guideline based on operating the appliance 24 hours a day, every day.

How to Choose the Best Air Purifier

Not all air purifiers are considered equal. And while activated carbon sounds impressive, research has shown that in most cases, not enough carbon is included in the filter to effectively remove odors from the air. For selected mashups, read PM2.5 vs HEPA filter, Trusens vs Dyson, room vs whole-house air purifiers, and air purifier CADR comparisons.

Likewise, most experts also agree that consumers should avoid any air purifiers that emit ozone (either intentionally or as an accidental byproduct) or rely on UV light. Too much ozone can create respiratory problems, especially in people who already have known breathing conditions. And in most cases, the exposure time frame programmed into UV-based air purifiers isn’t long enough to effectively kill any airborne pathogens.

Air Purifiers Key Factors to Consider

1. How large is the room you want to filter?

Just like air conditioners, air purifiers are designed to effectively filter the air in a set size. Check the appliance for the Association of Home Appliance Manufacturers (AHAM) seal. This confirms that the appliance is certified to effectively provide the clean air delivery rates (CADR) for the room size advertised. But remember it’s always better to pick an air purifier with a larger CADR than your intended room size than to pick one that’s too small.

2. How often do you want to replace the filters?

For your air purifier to work effectively, you’re going to have to replace the filter at some point. In most cases, this is anywhere from every three to six months, or every six to 12 months. While it’s not the most labor-intensive task you’ll ever complete, you’ll need to remember that along with the act of replacing filters, you also need to buy those replacement filters.

3. How much do you want to spend on replacement filters?

Filter prices can vary with HEPA filters being the most expensive option. Mechanical filters can range from budget-friendly to as much as $200 — with $80 being the average price. In contrast, activated carbon filters max out at $50 each.

4. Do you want a quiet operation?

This is especially important if you want an air purifier for a bedroom. Most air purifiers feature quiet operation modes which won’t emit more than 50 decibels. But if you find that a purifier rated for your room size is still too noisy, picking a higher CADR model can ensure that it can clean more air in a lower (and quieter) setting.

5. Does it come with a remote control?

This is more a function of convenience but may feel like a necessity for many people. Having a remote means that you can easily adjust settings without having to get up and manually touch the air purifier. In some cases, you can even find purifiers that come with compatible apps so you can use your phone to control it and not have to deal with searching for remotes.

6. How portable is the unit?

Especially if you think you might want to move your air purifier between rooms, looking for models that are set on wheels or feature carrying handles are important. These features just make it more convenient to move the appliance — especially as these models tend to be larger and can weigh between 10 to 20 pounds.

7. Does the air purifier have air quality sensors?

While this isn’t a requirement, it’s a nice feature if you want an air purifier that automatically adjusts operation. With this type of feature, the appliance relies on a sensor to detect the current air quality in the room and then adjusts the operation settings to either improve air quality or maintain the current output.

8. Are there filter indicator lights?

Even though you know that the filters need to be replaced, it’s nice to have indicator lights to serve as a visual reminder that you need to swap out the filters.

9. Is there a washable prefilter?

For people that want to extend the lifespan of every filter, a washable prefilter is a must. This is the first source where air enters the air purifier. A good prefilter can catch larger particles. Just make sure that you can easily remove and replace it.


Do air purifiers really work?

Air purifiers are effective at removing particles from the air. However, experts agree that unless you have a known respiratory concern, most people don’t need an air purifier in their homes.

What settings should you run an air purifier on?

This is going to depend on the current air quality in the room. But keep in mind that for the best results, you should be running the air purifier 24 hours a day, every day. In most cases, you can begin at a higher setting when you first start operation and then shift to a lower setting after a few hours.

What about air purifiers that produce ozone?

These types of air purifiers should be avoided — especially if anyone in the home has a respiratory condition. Many air purifiers that either rely on ozone generation or produce it as a byproduct, produce levels that exceed FDA guidelines. In higher levels, ozone can cause respiratory irritation and can even trigger worse outcomes for people that have asthma, bronchitis, or emphysema.

Dorian Smith-Garcia Profile image