Alen

Alen air purifiers are highly regarded for their impressive design, build quality and performance. This Texas-based manufacturer has developed an excellent reputation by being at the forefront of the industry for over 15 years.

Alen is also known for its above-average prices, and the BreatheSmart 75i, with a price tag of $799, is undoubtedly high-end. You might be here because you wonder whether it’s worth spending the extra money on this device, and that is why I bought an Alen 75i to test it in the same space I’ve tested over 100 air purifiers since 2020.

The overall score of the Alen 75i incorporates first-hand data results from our battery of tests, as well as our ratings for customer service, brand transparency and design & UX. Check out the full scorecard below to see the split of categories.

By the way, I originally reviewed the older BreatheSmart 75i back in 2022 and I have now updated my original review with the data of the newer 75i V2.

The pros and cons of the Alen BreatheSmart 75i 

A summary of our top-level findings after testing this air purifier following our methodology.

“For those looking for an air purifier for dealing with odors and VOCs in rooms up to 500 square feet, the Alen BreatheSmart 75i could be worth the $799 investment.

However, if you don’t have serious issues with gases and smells, then it might be overkill.”

ENERGYSTAR energy efficiency & AHAM CADR certificate

Filtration technology

The Dyson BP06 comes with a HEPA filter as standard, and you can choose between various options with different carbon quantities to suit your needs.

The first layer of filtration comes in the form of a removable pre-filter that sits in front of the HEPA filter.

As standard, the 75i comes with their Pure filter, which is a thick H13 HEPA filter without any carbon.

You can choose between Alen’s Fresh filter and their Odor filter if you want a combination of HEPA and pelleted activated carbon.

The Fresh filter has a thinner HEPA H13 combined with a carbon section that comes packed with 3.6 lbs of pelleted activated carbon.

The Odor filter also combines a HEPA 13 filter with less carbon but it has a catalyst to neutralize unwanted smells.

From all the air purifiers we have tested, the Alen 75i with its Fresh Filter has the third largest amount of carbon after the IQAir Healthpro Plus and Austin Air Healthmate:

We are developing our methodology for testing VOC removal and our preliminary data shows the 75i with the Fresh filter a great option for those wanting to remove orods and VOCs from the air. 

Design, controls and features

The 75i is a large air purifier with a laser particle sensor, smart functions and app connectivity.

The 75i is Alen’s largest air purifier and is much bigger than the 45i and the 35i.

Build quality is solid. The plastics feel dense with no creaking, and the panel seams are tight, giving it a premium feel. 

If you don’t want the plain white cover, there are five other options ranging from graphite to oak BUT you will need to pay a little extra.

Considering its size, I appreciate the large handle at the back and the wheels underneath for when you need to move it from room to room.

It comes with a laser sensor is that is much quicker to react to air pollution than the typical optical sensors we see in most air purifiers and doesn’t need to be cleaned regularly.

You also get an air quality indicator at the top. The LED ring changes color reacting to the pollution levels, going from blue (excellent) to green (good) to yellow (fair) to red (poor) and finally purple (very poor).

In terms of the control panel itself, I appreciate the clearly labelled buttons and the fact that all options are available without the need to use the smartphone app – which is a concerning trend I’ve noticed with new air purifiers.

Air cleaning performance

We tested the 75i V2 in our 728 cubic ft. test room, tracking how fast it removed all PM1 particles from the air after we filled the space with incense stick.

First, we tested 75i V2 running at each of its fan speeds in the same 728 cubic ft. test room where we have tested over 100 air purifiers.

When running at top speed, our PurpleAir Zen sensor shows the 75i needed 18 minutes to reach PM1 zero – and we estimate a PM1 CADR of 333 cfm which would be good enough to provide five air changes per hour in rooms up to 448 sq. ft.

For raw performance to $ spend, the Alen 75i provides more value for raw CADR than the IQAir Atem X, the Dyson BP06 and the Rabbit Air A3 but sits behind the Levoit EverestAir and the Smart Air Blast Mini.

But results at top speed won’t tell us the full story…

Sound levels

The sound levels of the Alen 75i range from 36.5 dBA to 57.5 dBA — quieter than popular models like the Winix 5510, the IQAir Atem X, and the Rabbit Air A3.

As part of our testing, I used a sound level meter to measure how much noise the Alen 75i generates at each of it fan speeds.

Reaching 57.5 dBA at top speed, the 75i is quieter than the Levoit EverestAir, the IQAir Atem X and the Rabbit Air A3 but it is louder than the Dyson BP06, the Airmega ProX and the Blast Mini from Smart Air.

At speed 2, it cleared our test room from all PM1 pollutants in 36 minutes, so we estimate a PM1 CADR at sub-45 dBA of 164 cfm based on the natural ventilation of the room. At this sub-45 dBA speed, it can provide five air changes per hour in rooms up to 246 square feet.

So when it comes to quiet air cleaning performance, the 75i outperforms the Dyson Big+Quiet BP06 but its performance is worse than every other large air purifier on the table:

Long-term running costs

Running a 75i will cost you $170.23 per year, combining energy consumption costs and filter replacement prices.

We measured how much energy the 75i uses when running at speed 1 (5.19 watts), speed 2 (13.27 watts), speed 3 (25.85 watts), speed 4 (33.99 watts), speed 5 (47.4 watts) and on standby (0.75 watts).

If you were to leave your 75i running at top speed 24/7 for one year, it would pull 411.7 kWh and add $52.21 to your annual energy bill, assuming an average U.S. electricity prices as of August 2025.

But energy costs are not the only thing you need to budget for – the filters need to be replaced, and this can become a significant expense, depending on the lifespan of the filter and how expensive replacements are.

Alen says you need to replace the filters for the 75i every 12-15 months, and as always, we will take the lowest estimate.
So you will need to buy one Pure Filter for $99 each year as a minimum, which leads us to a yearly running cost of $151.21 combining this with the electricity cost:

Thanks to the low energy usage and fair filter costs, the Alen 75i has the lowest running costs of all the large air purifiers we have benchmarked it against for this review.

And you can drop those yearly costs even further if you decide to go with a generic filter replacement from PUREBURG, which cost $75. That said, you will lose Alen’s lifetime warranty if you go the generic filter route, so you would need to decide if those $25 savings are worth losing that.

Bottom line: Should you get an Alen BreatheSmart 75i?

A powerful air purifier that can be customized with filters packed with carbon for serious odors and VOCs.

I have used Alen air purifiers for many years and something I can vouch for is how they continue to support older models. I still have my old A350 here in the basement and it not only works but I can still buy filters for it from Alen directly!

This means that when you choose to spend more on an air purifier from Alen, you know that you are investing in a device you will be able to run for as long as Alen exists.

And the fact that you can choose to go with the Fresh filter and get 3.6 lbs of activated carbon is a pro for me as it is a lot of carbon compared to what you get with most other air purifiers on the market today.

So for those looking for an air purifier for dealing with odors and VOCs in rooms up to 500 square feet, then the 75 could be worth the $799 investment.

The app is simple but works really well and the data you get from the laser onboard sensor offers accurate readings similar to those from a high-end air quality monitor.

So if that initial price doesn’t put you off, the Alen 75i is a solid contender for those looking for a premium air purifier.

But if odors are not a concern and you’re looking for a more powerful particle removal performance at a cheaper price, then look into the Levoit EverestAir (which sells for $499.99) or the Blast Mini which you can buy from Smart Air for around $700.

If you liked my review and want to support the work I do here at HouseFresh, please, use the affiliate links in the description and I’ll get a 3% commission at no extra cost to you.

Alen is a well-known brand in the world of air purifiers and the Austin-based company has been building air purifiers since 1999. They currently have 72 employees and had a revenue of just under 30 million dollars last year. 

One of their stand-out features is a lifetime guarantee — unique in the air purifier industry, but it does require you to sign up for their filter subscription. We have already reviewed the Alen 75i and 45i, which impressed us, although they are a little pricier than competitors with similar air cleaning performance. 

The Alen Breathsmart Flex is based on the 45i but lacks the ionizer and smart features. It still has a similar level of air-cleaning power and looks very similar. We were keen to test the performance of the Breathsmart Flex in our home and see if it matched the performance of the Alen 45i.

Most air purifier reviews are just pictures and overly optimistic write-ups. Journalists at these publications are biased to sell the unit without digging deeper than running the air purifier a few times.  We don’t have deals with manufacturers or a big corporation watching what we say, and we have no problem saying if an air purifier is terrible.

We don’t just take manufacturers at their word, either; we test all our units in our home lab to see how well they remove particles and share this data directly with you.

How we test air purifiers

Read our full testing methodology.

On paper, the Alen BreatheSmart Flex is very similar to the Alen 45i, although it lacks many smart features and an ionizer function. Read on to find out what differentiates these two Alen air purifiers.

The lowdown on the Alen BreatheSmart Flex

“A powerful and quiet air purifier without the bells and whistles you find with other models — that reduces the initial cost and you still get Alen’s lifetime warranty”

— Danny Ashton, HouseFresh Founder & Senior Writer

A fairly standard “Alen-looking” air purifier

The Alen Flex has a simple design and a small footprint considering its power.

You get a fairly standard Alen design with the Alen Flex, with a shiny white cover and a control panel on top. This is the same design you will see across other Alen devices in the BreatheSmart series such as the 45i and the 75i.

It doesn’t particularly stand out, but it’s also unlikely to be something to start a conversation for the wrong reasons.

The control panel is simple and straightforward, in line with other air purifiers by Alen.

From left to right:

• Filter indicator with three lights (green, yellow, red) to warn you when the filter needs to be replaced
• Timer button to set the air purifier so it runs for 2, 4 or 12 hours before turning off automatically
• Power button in the center to turn the unit on and off
• Speed button to switch between fan speeds (with the highest being Turbo speed)
• Lock button which allows you to lock the control panel after pressing and holding it for three seconds

Comparing the Alen Flex with the Alen 45i

If you have been researching Alen air purifiers for a while, you are likely to have run into another unit that looks A LOT like the Flex: the Alen BreatheSmart 45i.

When comparing the Flex to the 45i side by side, you will see that they both look as if they were to have been built from the same mold, with nearly identical design:

Both the Alen 45i and the Alen Flex have many of the same features, such as the child safety guard and a removable front cover that can be swapped out for five different colors.

The biggest difference comes when you compare the control panel of both units side by side:

The control panel of the Alen Flex lacks buttons for the ionizer, auto mode and options for adjusting the light. 

That means that unlike the 45i, the Flex doesn’t come in an in-built ionizer function (yay for those who prefer mechanical filtration only!) or with an auto mode (it does however come with a timer function, which is not the same but it’s good to have).

Something worth noting: The Flex does not offer app support.

That said, you can connect your Alen Flex with the Alen air quality monitor, enabling you to understand your air quality and enable intelligent air purifier features. However, the monitor costs $129. 

High quality customizable filters 

As default you will get medical-grade H13 HEPA filtration, but you can choose different levels of carbon filtration as well.

As with all the Alen air purifiers, you will get to pick from four different options when buying your Flex:

Every single Alen filter includes medical-grade H13 HEPA filtration that captures 99.9% of particles as small as 0.1 micron (e.g. dust, allergens, and harmful fine pollutants).

That said, my recommendation would be to get at least the FL40 Filter, as it comes with 2.3 lbs of activated carbon that can help remove unwanted smells and dangerous gases from the air.

The additional cost on top of the basic B4-Pure Filter is not a lot, and you will get an activated carbon filter in addition to the H13 HEPA filter:

But if you just want an air purifier for allergies and do not need gas or odor removal, you can save a little money with the B4-Pure Filter filter option.

I was pleased to report that the Alen Flex filter had an ample red warning to remove the plastic, so I can’t imagine anyone ignoring this. I wish more air purifier manufacturers would do this.

Changing the filter in the Alen BreatheSmart Flex is pretty straightforward. You just need to remove the back panel and you will be able to access the filters. Check out the video below for a step-by-step guide:

The Alen Flex cleared our test room in 34 minutes

That’s the exact same time it took the more expensive Alen 45i, which uses an ionizer!

As with all the reviews we produce at HouseFresh, we tested the Alen Breathsmart Flex in our test room, which measures 728 cubic feet. We burned an incense stick to simulate indoor pollution and used two Purpleair laser particle counter sensors to record how long it took for the Alen Flex to remove PM1, PM2.5 and PM10 particles from the air.

You can see the test results in the chart below:

As you can see, the Alen Flex cleaned our test room at the exact same speed as the upgraded Alen BreatheSmart 45i. It will be effective for small to medium-sized rooms. For those with large rooms, you will want to look at the much larger Alen 75i.

Noise levels test results, compared

As with the Alen 45i, the Flex is one of the quietest air purifiers we have tested here at HouseFresh. At its highest level, it hits a maximum of 50.7 dB(A), less than the sound generated by a standard refrigerator.

In comparison, many air purifiers with similar power levels can reach beyond 55 dB and the Mila and IQAir Healthpro Plus go up to 59.2 dB and 61.2 dB, respectively. One feature of Alen air purifiers is that they also utilize pink noise, which is meant to be even more sleep-friendly white noise. 

We know noise can be subjective, so here’s a video to allow you to hear the different noise levels associated with running the Alen Flex across each of the available fan speeds:

The cost to run an Alen Flex: $83,23 per year

This calculation assumes you will stick to OEM filter replacements from Alen.

1. Electricity costs = $25.23 per year

Even at the highest speed, the Breathsmart Flex only pulled 24.2 watts, which is MUCH LESS than many competing air purifiers with this level of air cleaning performance. This means you can leave this unit on without worrying about large energy bills. 

2. Filter costs = $58.00 per year

The Breathsmart Flex uses the same filter choices we see with the Alen 45i, and on average, they are a little higher than we see from budget brands like Levoit or Taotronics. For those looking for large amounts of activated carbon, you will also have to pay a little more as these filters cost more than the Pure version. 

If you don’t mind choosing non-Alen filters, you can get generic filters that cost $45.99 instead of $58 to reduce this cost a little.

Filter

Genuine Alen BreatheSmart Flex Replacement

Generic Unofficial Alen BreatheSmart Flex Filter Replacement

Technology

Alen FLEX Pure Filter Replacement (H13 Grade True HEPA)

H13 Grade True HEPA + 3 Pre-Filters

More information

Buy on Amazon

Buy on Amazon

Price

Price not available

$36.99

Filter

Genuine Alen BreatheSmart Flex Replacement

Technology

Alen FLEX Pure Filter Replacement (H13 Grade True HEPA)

More information

Buy on Amazon

Price

Price not available

Filter

Generic Unofficial Alen BreatheSmart Flex Filter Replacement

Technology

H13 Grade True HEPA + 3 Pre-Filters

More information

Buy on Amazon

Price

$36.99

Bottom line: Should you get an Alen Flex?

The perfect option for Alen fans who don’t want ionization technology and who don’t care about smart features.

The Alen Flex is the cheapest Alen air purifier sold. They can sell it at a lower cost than the Alen 45i as it lacks the ionizer and smart features. The Flex still benefits from the high level of air cleaning performance, filter options and lifetime warranty that all Alen brand air purifiers benefit from.

If you don’t mind giving up the smart and auto mode for timers, then the Alen Breathsmart Flex is an air purifier that will do an excellent job keeping small-medium-sized rooms clean. It doesn’t create too much noise and has very low energy consumption.

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.

Buy on Amazon

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.

Buy on Amazon

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.

Buy on Amazon

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:

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.

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

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

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.