Last updated on May 13th, 2022

There are a lot of air purifiers that are marketed as best for 300 – 400 square feet area. However, many of them aren’t capable of cleaning rooms of this size: they either aren’t reliable or just do not have high quality HEPA air filters.

So here I present for you my list of the best HEPA air purifiers for 300 square feet area. But before we start a few notes about my methodology of picking air purifiers for this comparison.

  • All air purifiers listed here either were tested by me, or people I know;
  • All of them use true HEPA air filter that is capable of filtering airborne particles down to 0.3 micron at 99.97% efficiency;
  • In addition, some of them were independently tested by Association of Home Appliance Manufacturers. Among other things, it tests air cleaners and assigns CADR ratings and area coverage for them. You see AHAM-Verifide text next to the room coverage of air purifiers that they have tested;
  • All air purifiers can remove allergens and providing relief for people with a breathing condition. They can provide at least 4.8 air changes per hour (ACH), making them extremely viable for people who suffer from allergies or any other breathing conditions (e. g. asthma).

Now let’s see which air cleaner is the best for 300 sq. ft. room.

Coway Airmega AP-1512HH: Simply The Best

Coway AP-1512HH Mighty Air Purifier Review
Filter Life:
Room Coverage:
Noise Level:
6 months (Replacement Filter)
233 Smoke / 246 Dust / 240 Pollen
326 sq. ft.
4.9 – 77.8 Watt
24.4 – 53.8 dB

Full Specs & Review

Best Deal on Coway Airmega AP-1512HH

Coway Airmega AP-1512HH a.k.a. Mighty Air Purifier is the best air purifier not just for 300 sq. ft. area but also by and large. This air purifier made by the Korean company Coway is extremely efficient in removing any kind of pollutants in a room, whether it’s dust, pollen, tobacco smoke or any other kind of smell due to the 3-stage filter system that includes pre-filter, HEPA filter and Activated Carbon filter.

For anybody convenience it features auto mode. By simply pressing one button the air purifier will use the built-in particle sensor to detect any type of airborne irritant and based on its number, adjust the speed accordingly. For example, if you put it in the kitchen and start cooking, the Coway Airmega AP-1512HH will increase the speed the moment it senses the smell build up, keeping the air clean.

In addition, it has an ionizer. It helps to remove dangerous particles from the air and keep it fresh. The ionizer can be turned off at any moment if you don’t like it.

This Mighty air purifier has a certificate of Energy Star and consumes almost 78 Watts of power at the maximum speed. It’s not the most energy-saving air cleaner, but it delivers on the promises and that’s the most important thing.

And the last two positive notes about the Coway AP-1512HH: it is quiet even at maximum speed and maintenance costs do not exceed $100 due to the long filter lifespan and their low price tag.

Winix PlasmaWave 5500-2 w/ Washable Filter

Winix 5500-2 Air Purifier Review
Filter Life:
Room Coverage:
Noise Level:
12 months (Replacement Filter)
Smoke 232 / Dust 243 / Pollen 246
360 sq. ft. (AHAM-Verifide)
70 Watt
27.8 – 54.8 dB

Full Specs & Review

Best Deal on Winix PlasmaWave 5500-2

Winix PlasmaWave 5500-2 has an identical cleaning system to the Coway AP-1512HH that incorporates pre-filter, HEPA filter, Charcoal filter and optional ionizer that is called PlasmaWave that can be turned off as well. Winix is also a Korean company (coincidence?) and manufactures most of its appliances there.

This air cleaner has similar area coverage, but it was certified by AHAM and it stands at 360 sq. ft. If you struggling with allergies or asthma, this is an ideal air purifier to put in a 300 sq. ft. room, as you can run it at lower speed, so it will produce even less noise but keeping the air fresh and clean.

The Winix can also be used at night due to the feature called “Sleep mode”. In this mode the air purifier runs almost silent, producing only light white noise that does not disturb in any way.

Another interesting feature I have to mention is its washable filters. Most air purifiers do not allow for washing of their filters (except for pre-filters), but the Winix does. As a result, it greatly extends the life of the filters, reducing the operating costs that do not exceed 100 USD including electricity bills.

Alen BreatheSmart 45i: Quiet, Great for Allergies & Heavy Smoke

Alen BreatheSmart 45i air purifier Review
Filter Life:
Room Coverage:
Noise Level:
1 year (Replacement Filter)
245 for Smoke/Dust/Pollen
380 sq. ft.
1.1 – 50 Watt
23 – 49 dB

Full Specs & Review

Best Deal on Alen BreatheSmart 45i

What makes Alen BreatheSmart 45i to stand out are:

  • The ability to clean air in 300 sq. ft. rooms while keeping the noise levels extremely low for an air purifier;
  • Filters customization: 4 custom filters are available for purchase and 3 of them specifically target allergies (including allergies from pet smell, hair and dander) and odor, while the last one shows great examples of removing any kind of smoke (tobacco, wildfire, etc.) in a room.
  • The Alen company provides a lifetime warranty if filter subscription is active at the official store.

However, the positive sides come at a cost: the BreatheSmart 45i retails at above $400, and filters aren’t cheap either. However, if you are ready to use the best solution for any kind of air pollutants and do not put with any kind of disturbing noise, then it’s the best what you can get for your medium-sized room.

It also comes with WiFi support, so you can control the air purifier manually from a distance if you do like the auto mode for some reason.

Medify Air MA-40: Best for Virus Removal

medify air ma 40 air purifier review
Filter Life:
Room Coverage: 
Noise Level:
4 months (Replacement Filter)
224 CFM for Smoke/Dust/Pollen
350 sq. ft.
46 – 66 dB
64 Watt

Buy at Amazon

Medify Air MA-40 is also an extremely popular air purifier that comes under $350 per one unit. It’s not quiet, but features large 3-in-1 medical-grade HEPA filters that remove all types of irritants, including viruses and bacteria. A HEPA H14 filter is available as a replacement, and it features even better particles removal down to 0.1 micron. It is a great news, as most of viruses fit into the category of 0.1 – 0.3 micron particle size.

The MA-40 features Auto and Sleep modes, timer, and child lock. Basically, the features you should expect for a machine of such magnitude from Medify.

However, the noise levels aren’t that uplifting. At the maximum speed it produces a whopping 66 decibels of sound that is somewhere between the normal conversation and office sounds. On a positive side, the powerful motor and excellent air filter clean the air quickly and thoroughly, so most of the time this air  purifier won’t be used at the maximum power.

In addition, the ionizer (passed CARB, available for shipping to California) makes the air smell fresh after each cleaning procedure.

Blueair Blue Pure 311 Auto: Excellent for Tobacco Smoke

Blueair Blue Pure 311 Auto Air Purifier Review
Room Coverage:
Noise Level:
6 months (Replacement Filter)
250 Smoke / 250 Dust / 244 Pollen
388 sq. ft. (AHAM-Verifide)
3 – 35 Watt
23 – 53 dB

Blueair Blue Pure 311 is a great air purifier if you are a smoker and your main concern is to remove cigarette smoke from any room whether it’s kitchen, living room, basement or bedroom up to 388 sq. ft. (yet it will clean the air from smoke in 400 square feet area as well). This air cleaner has passed AHAM certification and is sure to make the air clean from smoke and other types of pollutants, but mostly dust and pollen.

Blueair has also managed to keep the power consumption at only 3 Watts in Sleep mode, making it viable to run 24/7 for months without touching anything. This will keep the air clean throughout the whole time at a low maintenance costs: a few dollars per year for electricity and only $40 for the replacement filter every 6 month.

Honeywell HPA200: Old But Gold

Honeywell HPA200 air purifier reviews
True HEPA:
Filter Life:
Room Coverage:
Noise Level:
3 months (Replacement Filters)
Smoke 200 / Dust 190 / Pollen 180
310 sq. ft. (AHAM-Verifide)
62 Watt
50 – 69.6 dB

Best Deal on Honeywell HPA200

Honeywell HPA200 is a fairly old air purifier designed by the US company Honeywell. As any other air purifier I have reviewed here, it can be used for rooms over 300 sq. ft., but when compared to the Coway, Winix, Alen, Medify or Blueair, the CADR ratings are lower and, therefore, the room coverage is also affected in a negative way.

The HPA200 also doesn’t have a pre-filter, resulting in the HEPA filter wearing down more often. However, the replacements are cheap (at $20 per one unit), so it is not a big deal.

I recommend getting the Honeywell only if it’s sold at a discount; in other instances the air purifiers listed above are simply better at filtering bacteria, odors and viruses from the air.

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