The best medical-grade air purifiers, based on over 100 tests

Alen 75i Corner

For an air purifier to be considered medical-grade, it must have a HEPA filter classified as H13 or H14 under EN 1822 or ISO 29463 (to ensure it can remove 99.95% to 99.995% of MPPS—most penetrating particle size—particles) that has been individually leak-tested using aerosol challenge methods (to ensure there are no performance defects or bypasses).

A medical-grade air purifier can be a great help to people suffering from asthma or COPD, are immunocompromised or have any medical issue requiring clean air that is free of viruses, bacteria or tiny harmful particles.

how we test
How we test air purifiers

Read our full testing methodology.

Let’s look a little deeper into my top recommendations, along with four more high-performing air purifiers and a couple of units that you should avoid at all costs.

1. Staff pick: IQAir Healthpro Plus

When it comes to medical grade HEPA filters, IQAir is top of the game — the Healthpro Plus offers the highest grade HEPA on the market today.

If you’re serious about air quality, suffer from severe allergies and/or respiratory disease(s) or live in a highly polluted area, the IQAir Healthpro Plus is a unit you should look into. This robust air purifier is engineered and built in Switzerland, and each unit is rigorously tested before being sent out into the world.

What we really like

Cleaned our performance room in 25 minutes
HyperHEPA is the best in its class
V5-Cell filter contains over 5 lbs of activated carbon
The HyperHEPA filters can last up to 4 years

What we think could be better

It takes up quite a bit of floor space
The price is at the high end
There’s no app support or auto mode

When you look under the hood of the Healthpro Plus, you’ll find its three carefully engineered filters that maximize its efficiency at removing airborne particles. IQAir’s HyperHEPA filter is the main attraction, which removes 99.5% of particles down to 0.003 microns. To put that into context, the size of SARS-CoV-2 ranges from 0.07 microns to 0.09 microns.

Although the IQAir Healthpro Plus may look intimidating, it’s simple to operate and has a clear screen to navigate through its settings. Plus, there’s a remote control if you need it. There are no smart functions like an auto mode or app connectivity; the Healthpro Plus strictly concentrates on air quality over gadgetry.

If you’re looking for an extremely high-performance medical-grade air purifier…you’ve just found one.

Clean air delivery rate (CADR):– Top speed PM1 CADR: 213 cfm
– Sub-45 dBA PM1 CADR: 86 cfm
Filter technology:HyperHEPA and V50-CELL with 5lbs of activated carbon + zeolite mix
Recommended room size:319 sq. ft. (5 air changes per hour)
Dimensions:28H x 18W x 16D inches (71H x 38W x 41D cm)
Weight:35 lbs (15.88 kg)
Noise level in decibels from 3 ft. away:Speed 1: 36.9 dB
Speed 2: 37.2 dB
Speed 3: 40.9 dB
Speed 4: 47.2 dB
Speed 5: 53.9 dB
Speed 6: 61.2 dB
Electricity consumption in watts:Standby mode: 1 watts
Speed 1: 16.5 watts
Speed 2: 32.7 watts
Speed 3: 47.3 watts
Speed 4: 69 watts
Speed 5: 94.3 watts
Speed 6: 145.2 watts
Filter lifespan:4 years
Manufacturer’s warranty:10 years
Country of origin:Switzerland
Country of manufacture:Germany

Read our full review

2. The best performance per $ spent: AirDoctor AD3000 

If you’re looking for a fast-acting medical-grade air purifier that won’t drain your bank balance – the doctor is in.

AirDoctor AD3500 HouseFresh

A lot of marketing hype surrounds the AD3000, making big claims about its performance. And, if I’m honest, the hype is justified. The performance of this air purifier leaves many of its rivals in the dust (pun intended) with its UltraHEPA (medical grade) filter, auto mode, AQI and a CADR of 340 CFM.

What we really like

It cleared our performance room in just 14 minutes 
Auto mode is fast to react to air quality changes
Its UltraHEPA filter can last up to 12 months
Has an AQI on the front that is bright and easy to see

What we think could be better

Wish it had app connectivity to monitor air quality
Filter replacements are quite expensive compared to Levoit
Would be better if it had physical buttons on the control panel

Danny (HouseFresh founder) has the AirDoctor 3000 running in his bedroom over all the air purifiers we have because of its high performance and awesome effectiveness of its UltraHEPA filter at removing airborne pollutants down to 0.003 microns (100 times smaller than a standard HEPA filter).

As well as a medical grade filter, the AD3000 comes with the usual features we expect from modern air purifiers, like an auto mode, timer and light dimmer. It also features an ionizer that can be switched on and off (if you don’t like it).

Even though the price is slightly on the higher side, you’re paying for medical grade UltraHEPA filters and it’s one of the best performance per $ spent on the market today.

HouseFresh rating:★★★★☆
Time to clean our 728 cubic feet test room (with the device running at top speed):14 minutes (with ionizer function enabled)
16 minutes (without ionizer function)
Air purifier technology:UltraHEPA filter and dual-action Carbon/Gas Trap/VOC filter
Recommended room size (4.8 air changes per hour):521 sq. ft.
Clean air delivery rate (CADR):Dust: 339 CFM
Smoke: 336 CFM
Pollen: 356 CFM
Dimensions (in inches / in cm):19.87D x 27.16W x 12.38H inches (50.4D x 69W x 31.4H cm)
Weight (in pounds / in kg):18 lbs (8 kg)
Filter life:UltraHEPA filter: 12 months
Carbon/Gas Trap/VOC filter: 6 months
Noise level in decibels (measured from 3 ft. away with a sound level meter):Speed 1: 40.2 dB
Speed 2: 50.5
Speed 3: 58.2 dB
Speed 4: 63.6 dB
Electricity consumption in watts (recorded with an electricity usage monitor):Standby mode: 0.5 watts
Speed 1: 9.6 watts
Speed 2: 17.6 watts
Speed 3: 39.9 watts
Speed 4: 93.2 watts
Estimated running cost (electricity consumption + official filter replacement):$267.16 per year
Cost per CADR cfm (based on dust CFM as reported by AHAM):$1.53
Manufacturer’s warranty:1 year
Country of manufacture:China

Read our full review

3. The quietest option: Smart Air Blast Mini

A medical grade air purifier built like a tank – This powerful unit delivers a CADR of 450 CFM with ninja-like sound.

Blast Mini Living room

Smart Air doesn’t make air purifiers like other brands. You won’t find smart features, an AQI or control screens; they believe in the core science. 

The Blast Mini is a testament to these beliefs. There’s just one dial to control the fan speed…that’s it. But that’s not a bad thing, as they put all their efforts into engineering the Blast Mini into a high-powered air-cleaning beast.

What we really like

Cleaned our performance room in 12 minutes
Made from metal – built to last 
It has a high CADR of 435 CFM
It only produces 49 dB at its highest fan speed

What we think could be better

It’s a large and heavy unit
The control dial is on the back of the unit
Not as energy efficient as other units

Even though this large air purifier uses a high-performance fan, Smart Air has managed to keep its sound output to a minimum. The average maximum noise produced across all air purifiers we’ve tested is 64 dB; the Blast Mini kicks out just 56 dB at its highest fan speed and 45 dB at its lowest.

The medical-grade HEPA filter in the Blast Mini is enormous. Smart Air has wasted no room in this unit, as the filter takes up the whole front. This huge filter has a lot of surface area to capture pollutants so that it can last 12 months over the usual 6 months. This, combined with a large fan, makes the Blast Mini an excellent option for a medical-grade air purifier.

For many consumers, the main benefit of the Smart Air over the IQAir Healthpro Plus will boil down to price; it costs $600 vs $899 for the IQAir HealthPro Plus. All while providing faster results in our clean air test.

Clean air delivery rate (CADR):– Top speed PM1 CADR: 400 cfm
– Sub-45 dBA PM1 CADR: 272 cfm
– Manufacturer provided CADR: 437 cfm
Filter technology:H13 HEPA filter (and optional pelleted activated carbon filter)
Recommended room size:600 sq. ft. (5 air changes per hour):
Dimensions:22.6L x 13W x 24.8H inches (57.5L × 33W × 63H cm)
Weight:59 lbs (26.8 kg)
Noise level in decibels from 3 ft. away:Speed 1: 44.9 dB
Speed 2: 51.2 dB
Speed 3: 56.3 dB
Electricity consumption in watts:Standby mode: 0 watts
Speed 1: 51.9 watts
Speed 2: 87.4 watts
Speed 3: 122.7 watts
Filter lifespan:13 months
Manufacturer’s warranty:1 year
Country of origin:China
Country of manufacture:China

Read our full review

4. Best wall-mounted option: Smart Air SA600 

Smart Air proves that medical-grade air purifiers don’t need bells and whistles to be effective.

Smart Air SA600 Sofa area

Smart Air has solidified itself as a trustworthy brand in the world of air purifiers. Their no-nonsense approach to engineering over gadget ingenuity has proven highly effective. With a dual-inlet comprising two medical-grade HEPA filters and two activated carbon filters, the SA600 is no different.

What we really like

Cleaned our performance room in 33 minutes
Simple controls
Has filters on both sides of the unit
Very quiet throughout fan speeds

What we think could be better

No smart features like AQI or timer
Higher price tag than other units of this size
You have to replace 2 filters instead of 1

Compared to the Blast Mini, the SA600 couldn’t be more different on the outside, but it’s the inside that counts, right? This smaller unit still packs a punch and earned its spot in this guide with its dual H13 grade HEPA filters at the forefront of its cleaning performance.

These two medical-grade filters are engineered and tested to remove 99.97% of airborne particles in your home, like dust, pet dander, allergens and even viruses smaller than COVID-19. Combine that with Smart Air’s powerful fans and you have a strong deterrent against pollution.

Clean air delivery rate (CADR):– Top speed PM1 CADR: 249 cfm
– Sub-45 dBA PM1 CADR: 128 cfm
– AHAM PM2.5 CADR: 287 cfm (dust)
Filter technology:H13 TrueHEPA filter with a removable pre-filter and pelleted activated charcoal filter (set of two)
Recommended room size:373 sq. ft. (5 air changes per hour)
Dimensions:20 x 13.8 x 9 inches (51 x 35 x 23 cm)
Weight:15.5 lbs (7 kg)
Noise level in decibels from 3 ft. away:Speed 1: 35.2 dBA
Speed 2: 37.2 dBA
Speed 3: 41.5 dBA
Speed 4: 46.1 dBA
Speed 5: 56.7 dBA
Electricity consumption in watts:Standby: 0.1 watts
Speed 1: 2.4 watts
Speed 2: 4.3 watts
Speed 3: 7.1 watts
Speed 4: 12.9 watts
Speed 5: 53.8 watts
Filter lifespan:18 months
Manufacturer’s warranty:1 year
Country of origin:China
Country of manufacture:China

Read our full review

What to look for when buying a medical-grade air purifier

Medical-grade air purifiers use a HEPA grade filter known as H13, which can trap 99.97% of particles sized 0.3 microns or bigger. While this type of medical-grade filter will be able to capture tiny particles such as viruses, you will still need to ensure that you can provide enough airflow to clean the air in your room.

But, with so many medical-grade air purifiers on the market, it can be tough to decide which is right for your home. Luckily, there are guidelines to follow to make sure you get the most out of your new air purifier.

Here are the top things to consider when choosing a medical-grade air purifier that are often overshadowed, yet more important than the initial cost and design of the unit.

1. Has the HEPA H13 received confirmation by independent evaluation?

The use of the term HEPA H13 is not regulated, so it’s easy for air purifier manufacturers to use this terminology even when they haven’t tested their filters through an independent body.

With Levoit recently removing the HEPA term from their marketing, it’s not just smaller brands you need to worry about.

To avoid risking buying a device that isn’t HEPA H13, you need to stick to companies that prove that they have had their HEPA filters tested by an independent body. The EU rules are BS EN 1822-1:2019; for the rest of the world, you will want to look for ISO29463.

For those with serious medical issues, you are better off spending more money on a brand like IQAir or Smart Air that are very open about their independent testing and avoiding cheaper brands that seem to offer the same features at a far cheaper price.

2. How big is your room?

It’s not just the grade of the filter that counts; it’s also the air purifier’s performance. The size of your room heavily dictates which air purifier will work effectively in it. Using the measurement CADR (Clean Air Delivery Rate), we can calculate how effective an air purifier will be at cleaning the air in different-sized rooms.

The general rule is the larger the room, the higher the CADR is needed.

As well as CADR, you also need to consider ACH (Air Changes per Hour). While first-pass filtration is helpful, it’s even more critical that an air purifier can clean enough air to provide at least 4.8 air changes per hour.

For example, for a 350 sq ft room, you would need an air purifier with at least a CADR of 224 to provide 4.8 ACH (what the EPA recommends for portable air purifiers.) This is much lower than the 98 CFM that the Dyson combo units provide, meaning a room that size would still suffer from particulate pollutants.

It is essential that you accurately measure your room first, then work out what CADR you will need to clean it effectively. Feel free to enter your room size in our CFM calculator tool to see the CADR needed to keep the air clean in your room:

3. What are the long-term costs of running an air purifier?

For those wanting to keep the air clean all the time, you will need to ensure your air purifier runs 24/7, 365 days a year. If your air purifier is inefficient, it can end up adding a higher cost to your electricity bill.

It’s not just the cost of energy you need to consider, as all HEPA filters need replacing once they become full of particles. Eventually, airflow gets restricted so that they cannot clean as efficiently so you need to buy a new filter periodically to keep your air purifier performing to its highest standard. 

Some air purifier brands prey on consumers not thinking about the long-term costs when buying, so they offer cheaper units that cost much more in the long term in filter replacement costs.

There are now a lot of generic filters available for different models of air purifiers that cost much less, but if you are concerned about HEPA H13, be sure to stick to the genuine filters that will have been independently tested.

Common questions about issue

Most hospital buildings will use large air distribution systems incorporating MERV 8 pre-filters and MERV 14 final filters. High-risk areas like operating theatres will utilize medical-grade HEPA filters to achieve at least 15 air changes per hour to reduce the risk of infection. Other rooms will have different air change targets depending on the level of risk; you can see a full list of air change requirements at the CDC.

The filters that we find in air purifiers are rigorously tested beforehand. Each is rated on its ability to capture particles of different sizes. This is known as a Minimum Efficiency Reporting Values (MERV) rating, which ranges from a low H1 to a high H20.

According to NHS England, ionizers should be avoided as they have the potential to create chemical byproducts via secondary reactions. Currently, there needs to be more evidence of their efficacy in reducing microbial loads in the air.

According to the team at Commercial Air Filtration, HEPA H13 is better as it doesn’t restrict airflow as much, has a better filtration-to-airflow ratio and is less likely to suffer from air leakages.

For those with a medical issue, investing in an air purifier that uses filters with HEPA H13 is worth investing in. However, you still need to make sure that the air purifier has enough cleaning power to provide regular air changes for the space you are in.  Any type of air purifier will still be able to keep the air clean eventually, even if the grade of HEPA is lower as the airflow will be increased so the devices can move air quicker so even the MERV 13 of the Corsi-Rosenthal box can still remove the tiniest of particles from the air even though the filter it uses is lower than HEPA grade.

As air purifiers have become more of a requirement than a luxury item, doctors will most likely point out how running a unit in your home is a much healthier option than not. But it all comes down to your insurance plan. Many companies like Medicaid only cover DME (Durable Medical Equipment) which air purifiers (at time of writing) don’t currently fall under.

Wrapping up

Running an air purifier in your home is the best way to remove harmful airborne pollutants from your air. The scientific data to back this up is ample and well-documented. Air purifiers that contain a medical-grade filter will stop more particles in a single pass than low grade filters.

The trick is to find an air purifier that is right for your space and has enough power to utilize its high-grade filters efficiently and effectively. Each unit I have featured in this article is high-performing; some have more brains than brawn, and vice versa.

Alen A350 review

AlenA350 2

The Alen A350 managed to clean our test room of 700ft in 35 minutes which is better than the recent Levoit Core 300, which is an air purifier that we recommend and which cleaned the same room in 49 minutes.

Performance:

The downside of the A350 is its power consumption at a whopping 86.7 watts, which is equal to $133.67 a year in California’s electricity costs. Compare that to the far more powerful Levoit Core 400S that has 24.5watts at full power which would only cost residents of California $37 for the year it’s hard to recommend buying an Alen A350 but if you got one still in operation you don’t mind the extra costs of energy to save more plastic being thrown away then you might be tempted to keep it running.

The Alen A350 was an air purifier that was first sold in 2010, if you already have one of these units then congrats on keeping your unit running for 10 years. You will also be happy to know that you can still buy filters for these units:

Alen Air Filter BF25A-Fresh + Carbon Replacement HEPA Filter for A375 & A350 Air Purifier -Captures Allergens, Dust, & Mold + Odors & Smoke (1 Filter)
  • Silver-Ion Technology protects the filter against growth of harmful bacteria and microbes
  • Creates an allergy and asthma friendly environment by removing dust, pet dander, mold spores and pollen from the air
  • Provides pure, breathable air by capturing VOCs (Volatile Organic Compounds) from cleaning products, personal care items and other household materials
  • Pre-Filter layer extends the life of the filter
  • Our standard medical-grade H13 True HEPA air filter offers outstanding protection by removing 99.9% of dust, allergens, and harmful fine pollutants as small as 0.1 microns. Every 30 minutes, our product can purify your home or office air depending on the model of Alen air purifier.

Sadly the Alen A350 is no longer for sale but there are several new Alen units that you might be in interested in that have a similar specifications:

1. Alen BreatheSmart 45i

Alen Air Purifier BreatheSmart 45i HEPA with Pure Filter for Large Rooms up to 1600 Sq. Ft. - Perfect for Bedrooms - Captures Allergens, Dust, & Mold
  • HEPA Pure Filter: Eliminates 99.9% of allergens and pollutants as small as 0.1 micron so you can breathe easy. Ideal for allergy, asthma, and virus concerns.
  • Proven by SleepScore Labs to enhance sleep according to a peer study. Its ultra-quiet operation emits pink noise, optimizing lower octave frequencies, and ensuring a restful night.
  • The BreatheSmart 45i quietly and efficiently circulates air up to 1600 sq. ft. every hour. Perfect for large bedrooms, living rooms, and dining rooms ensuring clean, fresh air throughout your space.
  • Alen air purifiers offer superior performance through the combination of a powerful fan, quiet motor, and advanced filtration. Medical-grade filters capture particles as small as 0.1 micron.
  • SmartSensor technology adjusts fan speed based on air quality, with color-coded feedback. Monitor air purity easily with this home essential.

With a CADR rating of 245, the Breathsmart 45i would be the A350 for the modern era. This unit comes with the same Alen lifetime guarantee so you can expect this air purifier to keep performing beyond 2030!

2. Alen BreatheSmart T500 

Alen T500 Air Purifier, Quiet Air Flow for Large Rooms, 500 SqFt, Portable Air Cleaner for Allergens, Dust, Mold, Pet Odors, Bacteria, In White
  • COMPACT AND MIGHTY: Experience powerful air purification with the Alen T500 Air Purifier, designed to clean 500 SqFt every 30 minutes. Its compact size makes it a perfect fit for small bedrooms, walk-in closets, dens, nurseries, home offices, and utility rooms. Breathe fresh air without compromising on space or performance.
  • FRESH HEPA Air Filter: Breathe cleaner air with the Alen Air Purifier's high-quality HEPA filter. This advanced filter captures allergens, dust, mold, and germs, plus carbon to absorb common household odors, ensuring a healthier and safer environment for you and your loved ones.
  • MEDICAL-GRADE H-13 TRUE HEPA FILTER: Discover the exceptional power of our medical-grade H-13 True HEPA filter within your home. Our filter has an impressive 99.9% elimination rate of airborne particles as small as 0.1 micron, this technology guarantees clean and fresh air throughout your space. Take control of your indoor air quality and create a safe haven for your family.
  • EXTENDED FILTER LIFE: Say goodbye to frequent filter replacements. The Alen Air Purifier offers the convenience of extended filter life, lasting between 6 to 12 months. Enjoy continuous and hassle-free air purification without the worry of constantly replacing filters. Experience the freedom of clean air, day in and day out.
  • IDEAL FOR GIFTING: Show your loved ones you care by gifting them the Alen T500 Air Purifier, a versatile and essential addition to any home. Perfect housewarming gift for a new home, this purifier effectively removes allergens and impurities from the air, promoting a clean and fresh living environment. Its sleek design adds elegance while improving indoor air quality, making it a valuable household essential.

This unit is a little cheaper but still has a CADR rating for dust of 159 so less powerful than the A350 but can often be found for less than $250 so it is significantly cheaper. This is a low-priced unit but still comes with the Alen lifetime guarantee. This unit comes with the H13 which are the same filters used for medical-grade air purifiers.

The following article is our original review of the Alen A350 Air Purifier from 2010:

AlenA350 1

PRICE = $399 (Amazon.com)

Before we start to dig deep into the pros and cons of this particular purifier. It’s worth having a look at what consumers at the major retailers think of this purifier. Most large internet retailers allow consumers the ability to provide a rating for their purchase. I use this rating as an initial way to quickly gauge the performance of an air purifier.

Review SiteRating
Amazon.com4 Stars (30 reviews)
Epinions.com5 Stars (8 reviews)
Wize.com4.5 Stars (77 reviews)
Shopping.com4.5 Stars (8 reviews)
Air Purifiers America4.5 out of 119 (10 user reviews)

The Alen a350 purifier has achieved favorable scores across a wide range of sites.

Note: Air Purifiers America has business connections to Alen so we need to take their scores less seriously than the other more independent retailers.

The video below will take you through a sample of Amazon.com reviews so you can get an idea of what people like/dislike about it:

The next step we take for this air purifier review is to dig a little deeper into what the experts are saying about this purifier:

1. Air Purifier Power – Written By Ed Sherbenou

AlenA350 5

Air-Purifier-Power Rating: 82, good

Benefits:

  • In recent assessments by air-purifiers-america.com this A-350 eliminated 98% of the contaminants in the device and 97% of the contaminants within the room.
  • The A 350 purifier is great at airborne dirt and dust and plant pollen elimination, yet is also competitively cost-effective costing under $300..
  • So the projected CADR (for basic comparability to mid priced store-bought models without having chemical substance blocking capability ) is 203.
  • The manufacturer guarantees 95% of purchases will be delivered within Twenty-four hours, and also features a straightforward return policy.

Problems:

  • Significant gas and smell elimination is really a necessity if health benefits can be envisioned: Models with actual carbon VOC ability position higher.
  • Alen A350 air purifier sound amounts will be over normal: 36 decibels(A)on low setting, 65 decibels(A)@214cfm on highest setting. 65 decibels(A) isn’t the loudest, but 214cfm is fairly weak for that amount of noise.
  • The organization doesn’t sell direct, yet drop ships air cleaners marketed by merchants.

2. ConsumerSearch.com

Webp.net gifmaker 1

Provides some reservations that the A350 should only be used in smaller rooms.

Benefits:

  • Highlights that this particular purifier can be mounted on the wall
  • States that the replacement filters  are relatively cheap
  • Mentions that the A350 comes with a Lifetime warranty

Problems:

  • Talks about how come, consumers, mention that the power supply causes a “humming” sound
  • Indicates that this air purifier should only be used in smaller rooms

CADR Results:

Sadly the A350 has not undergone a CADR test so we can not provide these results for this test. Thankfully Ed at air-purifier-power has worked out that this purifier has a similar ranking to a CADR ranking of 203.

The Alen A350, therefore, has an estimated score of: 203 CADR Ranking

Technology Used:

1.HEPA Filter

The Alen A350 uses one combined HEPA, carbon, and pre-filter in one unit. The only issue this raises is the price as the purifier requires this combined filter to be changed every six months. Currently, you can purchase the A350 filters on amazon.com for $49.99 which is not too bad but bear in mind that you will need to replace these twice each year – so it’s $100 per year. If I compare this with other purifiers that use Lifetime HEPA such as the Honeywell 50250-N, the A350 is considerably more costly to run.

2. Ionizer Function

One of the nice benefits of the Alen A350 is that it comes packaged with an inbuilt non-ozone ionizer unit. Normally I would suggest that people steer clear of ionizer-only units but when combined with a strong HEPA filter it can help improve cleaning efficiency. The ionizer unit will charge the surrounding particles with a negative charge which means that these particles are heavier and thus picked up more easily by the HEPA filter. Negative ions have also been shown to imbue of sense of well-being but this still has not been confirmed by scientific studies. If you are not sure about the ionizer then you can easily disable the function using the on-off switch at the top of the unit.

Power Consumption

The A350 has an Energy Star Rating but compared to modern air purifiers it’s uses a lot of electricity with a maximum of 86.7 watts.

Addressing the Sound Problem

Some reviews have mentioned that the A350 has a whining sound when running. In tests, we came across no such noise and believe that this whining sound was down to broken air purifiers. On the highest setting, the A350 creates a noise level of 65 dB, which is relatively loud. In the video below I show the Alen a350 working at each different sound level so you can evaluate if it’s too loud for your home. 

While the purifier is loud at the level 5 setting, it’s unlikely that you would need to leave it at this level for much time. I am quite happy with the sound output at the lowest level and so I would not find a problem sleeping with it running in my bedroom.

Performance Test

To test the A350’s performance, we set it up in our HouseFresh testing room.

We use this 705 cubic ft bedroom to test all our air purifiers to ensure it is done fairly, in the same conditions for a more accurate comparison.

To create pollution, we use incense sticks which contaminate the room with large amounts of pollutants. When the room is sufficiently polluted, we turned the Alen on at full fan power and left it to see how long it took to clear it of contaminants.

As with all our performance tests, we used the Purple Air Indoor sensor to track the number of small particles down to 1ug in the room, in real-time, allowing us to view the data on a graph.

Here’s what we found:

The highest point on the graph is where pollutants from the incense reach their maximum contamination.

As you can see from the sharp drop, the A350 goes straight to work on the larger particles in the room, while dealing with the smaller ones at a slightly slower pace.

The A350 cleared the room of contaminants in 35 minutes. Even though this unit is no longer sold, it holds its own against the newer, more modern units on the market.

Conclusion

This purifier provides a significant amount of cleaning for a small price of just under $400. It can be used in medium-sized rooms (400 square feet recommended) and can successfully remove all types of particles. My only issue with this purifier is the cost of replacement filters ($100 annually) and the lack of VOC capabilities.

When comparing with other purifiers, you should make sure that you take into account the $100 a year cost, as some Lifetime HEPA filters will work out far cheaper in the long run and may outweigh the initial extra cost.

The Alen A350 air purifier is currently the highest-rated purifier in my medium range ($200-$700), and I give it a 5-star rating.