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6 best air purifiers for asthma, according to our test data

The following air purifiers utilize HEPA filtration to remove the tiny particles that trigger asthma
By
Updated on April 14, 2024
Written by
Danny Ashton
Danny is the founder of HouseFresh and has been writing about air purifiers and indoor air quality since 2010. He is our lead tester, conducting all the tests we use to evaluate air quality products. That is why you will always see his name attached to our reviews.

Our verdict

 

  • Are you looking for an air purifier to help eliminate asthma triggers? You can’t go wrong with the mighty Levoit EverestAir.
  • On the hunt for a powerful yet quiet air purifier that can be used during the night? Then you should go with the Smart Air Blast Mini.
  • Are you on a tighter budget but still need to clean the air in a large space? Then the Levoit Core 600S is your best bet.
  • Looking for a unit to be placed in a small room (up to 403 sq. ft. )? In that case, we recommend the Levoit Core 400S.

A study from 2020 showed that air purifiers could help asthmatic children to use less medication to keep their asthma symptoms in check as it can reduce the amount of PM2.5 particles in the air. However, not all air purifiers will help reduce symptoms — a study that used Dyson air purifiers could not significantly improve asthma control.

An air purifier can help reduce the number of tiny particles in the air from air pollution and dust mites that can aggravate asthmatic symptoms. True HEPA is very effective at removing these small particles but also needs a powerful fan to push enough air through the filter.

To keep asthma symptoms at bay, you must ensure that the air purifier you choose has a high level of air cleaning performance (CADR) so you can have at least 4-5 air changes per hour. The larger the room, the higher the CADR you will need.

  1. In our home lab of 728 cubic feet, we light an incense stick to generate particle pollution and VOCs.
  2. We set up our trusted Purpleair Indoor Sensor with the latest Bosch gas sensor to track levels of PM1ug/m3, PM2.5ug/m3 and PM10ug/m3 and VOCs in the air.
    purpleair
  3. We switch the air purifier to its highest speed and measure how long it takes to get our room air quality down to PM1 level to 0.
  4. We use an energy meter to measure precisely how much electricity is used when running the unit at the lowest and highest fan speed settings.
  5. We track sound levels emitted by the air purifier at different fan speeds with the help of a commercial sound meter.
    sound meter

Armed with our test data, we can see which air purifiers would solve specific problems. When picking air purifiers for asthma, we ensured all of them had the following: 

✅ True HEPA or higher HEPA grade — Pollen and PM2.5 from pollution are the primary triggers for asthmatics. So we only chose air purifiers that utilize this as their primary filter technology.

✅ High CADR:  An air purifier with a low CADR score might be unable to remove all particulate pollutants quickly enough, so we have only included recommendations with a minimum CADR of 225 CFM. 

✅ No ionization technology:  While the ozone level is safe at 50 ppb for modern ionizer units like the Blueair HEPASilent, we avoided recommending those units in favor of mechanical filtration with zero byproducts.

The top 3 air purifiers for asthma

If you don’t have time to read our 3000+ word guide to the best air purifiers for those with asthmatic symptoms, these are the three air purifiers we currently recommend based on our own testing:

BEST OVERALLQUIET OPTIONBEST VALUE OPTION
Levoit EverestAirSmart Air Blast MiniLevoit Core 600S
Air cleaning speed13 minutes17 minutes15 minutes
CADR360 CFM (612 m3/h)435 CFM (740 m³/h)410 CFM (697 m³/h)
Filter technologyPre-filter, particle filter and activated carbonH13 medical-grade HEPA filterPre-filter, particle filter and activated carbon
Max. room sizeUp to 558 sq. ft.Up to 915 sq. ft.Up to 635 sq. ft.
Weight20.7 lbs (9.38 kg)59 lbs (26.8 kg)13.7 lbs (6.2 kg)
Our reviewEverestAir reviewBlast Mini reviewCore 600S review
Price$499.99$599.00$249.99

Last update on 2024-04-21 / Affiliate links / Images from Amazon Product Advertising API

Check out the six air purifiers for asthma that will help you to reduce symptoms in your home:

1. Best overall: Levoit EverestAir

Having tested the EverestAir at HouseFresh, we were so impressed by its results that it quickly became one of our favorite units, surpassing expectations across various needs and uses.

When it comes to asthma allergens, the main filter inside the EverestAir’s hood can filter fine particles as small as 0.3 microns and clean the air from asthma-triggering particles with impressive filtration efficiency.

Thanks to its high CADR score of 360 CFM and an efficient Auto Mode that adjusts fan speed based on pollutants using a built-in three-channel dust sensor, it can deliver constant fresh air with a good performance ratio to energy costs. Plus, it can do it fast. The EverestAir thoroughly cleaned our test room’s air in 13 minutes. 

Although it’s a large unit, its new design is nothing like the bulky Core range; its sleek, futuristic aesthetic reduces its footprint. And it’s packed with smart features and app support. 

What we really like

A washable pre-filter extends the HEPA filter’s life
Fastest at removing particles measuring in 1 micron, so will be able to deal with allergen-causing particles that are much bigger
It’s very quiet in slow fan speed mode, close to silent, but it was still able to clean our test room in 30 minutes
Displays reading on indoor PM1.0, PM2.5 and PM10 levels on the control panel with a high-quality screen
Includes a large, activated carbon filter to also deal with VOCs and gasses

What we think could be better

High initial price in the same price range as the IQAir Healthpro Plus
Some issues have been made on Levoit removing the HEPA from their marketing

SPECS & FEATURES

HouseFresh Rating:★★★★★
Time to clean our test room:13 minutes
Air purifier technology:3-Stage Filtration (Pre-filter for large particles, main filter for airborne particles, high-efficiency activated carbon filter for odors and gasses)
Recommended room size:558 sq. ft.
Clean air delivery rate (CADR):360 CFM (612 m3/h)
Dimensions (in inches / in cm):18.9L x 8.5W x 23.2H inches (48L x 21.6W x 58.9H cm)
Weight (in pounds / in kg):20.7 lbs (9.38 kg)
Noise level (low – high):24 – 56dB
Filter life:12-15 months
Warranty:2 years
Estimated energy consumption:$87.25 per year
Country of manufacture:China

2. Quietest option: Smart Air Blast Mini

The Smart Air Blast Mini is a giant air purifier with one significant advantage over the other units on this list — its ability to clean without exceeding 49dB is impressive, considering it cleaned our test room in 17 minutes.

If you need to keep a larger space free of particles that could aggravate asthma and need it to be as quiet as possible – the Blast Mini from Smart Air should be at the top of your list.

The Blast Mini is a large air purifier, so it might be overkill for those looking to keep a small bedroom free of particles, but this is perfect for those looking for large spaces. 

I like that Smart Air allows you to choose a HEPA-only filter when you purchase rather than the integrated HEPA + carbon filter that we see with the Levoit purifiers. 

What we really like

Pure mechanical filter, no ionizer
High performance with a low max sound output of 49dB
Filter costs are fairly priced, considering their size and how often they need to be replaced
HEPA H13 as standard with optional carbon filter – not required for particulate removal

What we think could be better

High initial cost and energy usage might be overkill for smaller spaces
No smart features like app support or auto-mode

SPECS & FEATURES

HouseFresh Rating:★★★★☆
Time to clean our test room:17 minutes
Air purifier technology:H13 HEPA Filter
Recommended room size:915 sq. ft.
Clean air delivery rate (CADR):435 CFM (740 m³/h)
Dimensions (in inches / in cm):22.6L x 13W x 24.8H inches (57.5L × 33W × 63H cm)
Weight (in pounds / in kg):59 lbs (26.8 kg)
Noise level (measured from 3 ft. away):Speed 1: 44.9 dB
Speed 2: 51.2 dB
Speed 3: 55.8 dB
Filter life:33 months
Electricity consumption (kilowatt-hour):Standby mode: 0 kWh
Speed 1: 51.9 kWh
Speed 2: 87.4 kWh
Speed 3: 122.7 kWh
Estimated running costs (electricity consumption + filter replacements):$277.70 per year
Manufacturer’s warranty:1 year
Country of manufacture:China

3. Best value for money: Levoit Core 600S

The Levoit Core 600S had a ton of air-cleaning power and cleaned our test room in 15 minutes, which used to be the quickest we had seen before the EverestAir hit the scene. It also comes with many smart features, from app support to an auto-mode that adjusts fan speed depending on the amount of pollutants in the air.

The Core 600S, like the IQAir HealthPro, is a large unit, and while it contains far less carbon, it still uses pellets, which are the best form for picking up chemicals and odors. 

The Levoit Core 600S has one of the best ratios of performance to $ spent with a CADR of 410 CFM for less than $300. While this unit is large, you can also utilize it in smaller bedrooms at a lower speed for a high level of air cleaning with a very low level of sound generated. 

What we really like

Cleaned our test room in just 15 minutes
Includes smart features like auto-mode and app support for Android and Apple
Filter uses HEPA H13 and pelleted carbon
The price-to-CADR ratio is one of the best on the market

What we think could be better

A large device a fairly dull design
Made in China, build quality is not as high as other units on this list

SPECS & FEATURES

HouseFresh Rating:★★★★★
Time to clean our test room:15 minutes
Air purifier technology:3-Stage Filtration (Pre-filter for large particles, main filter for airborne particles, high-efficiency activated carbon filter for odors and gasses)
Recommended room size:635 sq. ft. 
Clean air delivery rate (CADR):410 CFM (697 m³/h)
Dimensions (in inches / in cm):12.3 x 12.3 x 23.6 inches (31.3 x 31.3 x 60 cm)
Weight (in pounds / in kg):13.7 lbs (6.2 kg)
Noise level (measured from 3 ft. away):Speed 1: 40.9 dB
Speed 2: 45.9 dB
Speed 3: 61.4 dB
Filter life:6 months
Electricity consumption (kilowatt-hour):Standby mode: 1.53 kWh
Speed 1: 7.92 kWh
Speed 2: 11.35 kWh
Speed 3: 21.15 kWh
Speed 4: 49.27 kWh
Estimated running costs (electricity consumption + filter replacements):$107.29 per year
Manufacturer’s warranty:2 years
Country of manufacture:China

4. Levoit Core 400S

The Levoit Core 400S is the smaller brother of the 600S and has all the same smart features, including auto mode and app support. In our home lab performance test, this air purifier thoroughly cleaned our room of particulates in 33 minutes.

The Core 400S is much smaller than the Core 600S, making it much easier to live with in a smaller room. Size aside, this air purifier can still clean the air over four times an hour for a space up to 450 sq. ft. Levoit air purifiers’ popularity means you can find many generic filters for this unit for as low as $25 per filter. 

For those with asthma, the Levoit Core 400S will easily keep your air free of dust mite particles and traffic pollution.

What we really like

Good ratio of performance to budget
Powerful enough to keep air clean of particles up to 450 sq. ft.
Same app and auto-mode that you find with the higher cost Core 600S
Not too big, so it takes up less floor space than the larger Core 600S

What we think could be better

Not powerful enough for larger spaces — need to upgrade to the Core 600S
Only 1-year warranty

SPECS & FEATURES

HouseFresh Rating:★★★★☆
Time to clean our test room:33 minutes
Air purifier technology:3-Stage Filtration (Pre-filter for large particles, main filter for airborne particles, high-efficiency activated carbon filter for odors and gasses)
Recommended room size:403 sq. ft.
Clean air delivery rate (CADR):260 CFM (442 m³/h)
Dimensions (in inches / in cm):10.8L x 10.8W x 20.5H inches (27.4L x 27.4W x 52H cm)
Weight (in pounds / in kg):14.1 lbs (6.4 kg)
Noise level (low – high):24 – 52dB
Filter life:6 months
Manufacturer’s warranty:2 years
Estimated energy consumption:$39.95 per year
Country of manufacture:China

5. Alen BreatheSmart Flex

The BeathSmart Flex is the simplified version of the flagship Alen 45i, but this version has no smart features or optional ionizer. In return, you pay much less for similar air cleaning performance; the Flex cleaned our test room in 34 minutes and only pulled 24.2 watts at its highest speed.

All Alen air purifiers have the possibility of a lifetime warranty when you purchase the filter subscription. When most air purifier brands have only a standard 1-2 year warranty, having something last a lifetime is impressive. 

Another significant benefit for those with asthma is the filter options you can choose when you purchase. To get the most effective removal of particles that aggravate asthma, we recommend going for the B4-Pure Filter, which is 100% HEPA H13 and costs the least of all the filter options. 

What we really like

A lifetime warranty is unique to Alen
Competitive initial price (currently $100 off, so $249, but normally $349) 
It only hits 50dB at maximum speed and utilizes “Pink noise,” so easy to sleep with
Filter choices mean you can customize a filter that is best for your specific needs
Great clear screen onboard sensor
Nearly silent on the lowest fan speed and still able to clean our test room in 25 minutes

What we think could be better

You don’t get any app support or auto-mode – this needs an upgrade to the 45i
The lifetime warranty is only active if you have a filter subscription

SPECS & FEATURES

HouseFresh Rating:★★★★☆
Time to clean our test room:34 minutes
Air purifier technology:H13 HEPA with an option for activated charcoal (Fresh, Odorcell and Heavy Smoke options available)
Recommended room size:700 sq. ft.
Clean air delivery rate (CADR):225 CFM (Smoke:  191 / Pollen: 245 / Dust: 209) 
Dimensions (in inches / in cm):25H x 15W x 8.5D inches (63.5 x 38.1 x 21.59 cm)
Weight (in pounds / in kg):15 lbs (6.8 kg)
Noise level (measured from 3 ft. away):Speed 1: 35.7 dB
Speed 2: 45.5 dB
Speed 3: 50.7 dB
Filter life:Every 9-12 months
Electricity consumption (kilowatt-hour):Standby mode: 0.8 kWh
Speed 1: 2.9 kWh
Speed 2: 6.3 kWh
Speed 3: 14 kWh
Speed 4: 24.2 kWh
Estimated running costs (electricity consumption + filter replacements):$94.23 per year
Manufacturer’s warranty:Lifetime (with product registration & active filter subscription)
Country of manufacture:China

6. IQAir HealthPro Plus

Let’s get the tricky bit out of the way; this air purifier isn’t cheap. 

At $899.99, it’s one of the most expensive air purifiers on the market but also one of the best. Made in Switzerland, each unit is tested before it leaves the factory. It utilizes its own patented HyperHEPA filter — perfect for eliminating asthma-causing pollutants, combined with a large, activated carbon filter with 5 lbs of carbon pellets.

You get a remote control but no smart features like an onboard sensor or app support. The IQAir Healthpro Plus has one of the largest HEPA filters we have seen and a very powerful fan; it removes all the pollutants in our test room in 25 minutes. 

If you can afford it, this is the air purifier we recommend for those with asthma.

What we really like

Swiss made from one of the oldest brands in the air purifier industry
The High-quality HyperHEPA filter is one of the largest we have seen used in a residential air purifier and has been third-party lab tested
A large amount of carbon filtering with gases, VOCs and odors
Wheels make it easy to move into different rooms as required

What we think could be better

Design is fairly utilitarian
High price for initial purchase and filter replacements

SPECS & FEATURES

HouseFresh Rating:★★★★★
Time to clean our test room:PurpleAir Touch: 24 minutes
PurpleAir Zen: 28 minutes
Air purifier technology:HyperHEPA and V50-CELL gas and odor filter
Recommended room size:450 to 1,125 sq. ft. 
Clean air delivery rate (CADR):300 CFM (510 m³/h)
Dimensions (in inches / in cm):28H x 18W x 16D inches (71H x 38W x 41D cm)
Weight (in pounds / in kg):35 lbs (16 kg)
Noise level (measured from 3 ft. away):Speed 1: 36.9 dB
Speed 2: 40.9 dB
Speed 3: 47.2 dB
Speed 4: 53.9 dB
Speed 5: 61.2 dB
Speed 6: 69 dB
Filter life:4 years
Electricity consumption (kilowatt-hour):Standby mode: 1 kWh
Speed 1: 16.5 kWh
Speed 2: 32.7 kWh
Speed 3: 47.3 kWh
Speed 4: 69 kWh
Speed 5: 94.3 kWh
Speed 6: 145.2 kWh
Estimated running costs (electricity consumption + filter replacements):$437.34 per year
Manufacturer’s warranty:10 years
Country of manufacture:Switzerland / Germany

Comparing our top picks for asthma: Air cleaning speed

As we test all our air purifiers in the same room, we compare different models and brands by looking at how long they took to reduce the PM1 level to zero:

Regarding air cleaning performance, the Levoit EverestAir wins by some distance with its impressive air cleaning speed of 13 minutes.

Comparing our top picks for asthma: Noise levels

We tested the sound levels for each of the air purifiers on our list at both the lowest and highest fan speed and used Flourish to visualize this data:

The Alen BreathSmart Flex is the quietest air purifier on average, while the loudest is the IQAirHealthPro Plus. 

What to look for in an air purifier to help with asthma

To get the right air purifier for asthma, you need to consider the following:

1. The size of the room

Bigger rooms will need bigger air purifiers, especially for those looking to use air purifiers to reduce asthmatic symptoms. HEPA filters do a great job of catching tiny particles, but for a larger space, you need to push a lot more air through them, which needs a bigger fan. 

Below we calculated the room size for the asthma air purifiers we recommend above, assuming 8ft ceilings and aiming for around 4.5 air changes per hour.

Air PurifierRoom SizeCADR
Alen BreatheSmart FlexUp to 400 sq. ft225 CFM (382 m³/h)
Levoit Core 400SUp to 450 sq. ft260 CFM (441 m³/h)
IQAir Healthpro PlusUp to 600 sq. ft.330 CFM (560 m³/h)
Levoit Core 600SUp to 700 sq. ft410 CFM (696 m³/h)
Smart Air Blast MiniUp to 800 sq. ft. 435 CFM (739 m³/h)

Feel free to use our CADR calculator to work out the CADR you will need to achieve 4.8 air changes per hour in your room:

2. True HEPA filter

Unlike issues with odor or VOCs, the main issue for those with asthma is the tiny particles caused by traffic pollution or the waste from dust mites that enter the lung and cause allergic symptoms that trigger asthmatic episodes.

When choosing the best air purifier for asthma, you should prioritize units that feature a high-grade HEPA filter over those with activated carbon, which is better suited to issues associated with gasses and odors.

Some brands like Smart Air allow you to choose only a HEPA filter when you buy, which means you will get better performance than using an activated carbon filter at the same time, and you also save a little money on the initial purchase.

Alen also allows you to customize your filter choice and has one option perfect for those with asthma: the Pure Filter is 100% H13 HEPA and will most effectively remove tiny particles from the air. 

3. Budget

Many air purifier brands will provide room size recommendations based on 2 or even 1 air change per hour. If you take this recommendation for an issue such as asthma and allergies, you will be satisfied as you must aim for at least 4 air changes per hour. 

Unless you have a tiny room, you should avoid a small air purifier if you want to deal with asthma symptoms successfully. While we love the Levoit Core 300, its CADR of 145 CFM is unlikely to bring relief to most average-sized American room sizes, and it’s why we suggest the higher-cost but more powerful Levoit Core 400S for those with asthma. 

Those on a limited budget should keep their smallest room clean of particulates, as can be achieved with a smaller/lower-priced unit.

FAQs about using an air purifier to help ease asthma triggers

Asthma triggers vary for each person. However, when triggered, the muscles around the airways tighten, resulting in symptoms like:

  • Chest tightness or pain
  • Coughing
  • Wheezing
  • Difficulty breathing
  • Inability to breathe while lying down

While asthma isn’t curable, symptom management is possible. Reducing or removing the trigger sources may be one of the most effective strategies. 

Using an air purifier that can effectively deal with allergens and air pollutants reduces your exposure to asthma triggers in your home.

Reducing the pollutants that trigger asthma attacks can immediately improve the air you breathe. These include tobacco smoke, pet dander, mold, dust mites and outdoor pollution – all of which are particles that an air purifier with a HEPA filter can remove from the air. Another way to improve the air to help ease your asthma is to use a dehumidifier to ensure that the humidity level doesn’t exceed 50%. 

For more tips, check out the CDC guide to asthma triggers.

In most cases, an air purifier is always good for asthma as it can help remove small particles in your air that trigger asthma episodes. If you have dry air, a humidifier might help, and if you are in a damp location, a dehumidifier can keep humidity levels in a safe zone for asthma symptoms. 

A recent study showed that a temperature of 68 and 71°F and a humidity level between 30-50% is the best air condition for those with asthma. You will also want to keep the amount of PM2.5 particles as close to zero as possible, which HEPA air purifiers are great at.

Wrapping up

Twenty-five million Americans suffer from asthma and while modern treatments have been great at reducing symptoms, there are still a lot of changes you can make in the home that can help without needing more medication. 

Someone with asthma has a susceptible respiratory tract and is hyperresponsive to substances that may not impact others similarly. These substances, often called triggers, can spark asthma episodes and symptoms.

Many people with asthma understand the need for vacuum cleaners to keep dust levels minimal, but dust is not the only trigger.

Dust mites
Pollen
Mold
Pet dander
Smoke (from cigarettes, other tobacco or marijuana products, and fires)
Outdoor air pollution, such as smog
VOCs, chemicals or strong fumes

Using a HEPA-based air purifier can effectively remove these tiny particles, keeping your air continuously clean and reducing the chances of an asthma episode.

Last update on 2024-04-21 / Affiliate links / Images from Amazon Product Advertising API

About the author

Danny Ashton

Danny is the founder of HouseFresh and has been writing about air purifiers and indoor air quality since 2010. He is our lead tester, conducting all the tests we use to evaluate air quality products. That is why you will always see his name attached to our reviews.