Okaysou AirMic4S Medical-grade Air Purifier Review

Basic Info

Okaysou is a newcomer to the air purifier market having just started in 2018. However, in such a short time they have managed to gain quite a lot of popularity. Based on using the AirMic4S, I would have to say their popularity is deserved and they earn it by making a user-friendly product.

They started with the AirMax8L which is rated for rooms up to 500 square feet. However, my apartment humble one bedroom apartment in the city is only a little over 400 square feet and divided amongst three distinct areas. Fortunately for me, Okaysou has added a small model, the AirMic4s, that matches my needs and at an even more affordable price-point than the AirMax8L

I’ll be doing a thorough review, but for those of you who cannot wait for the highlights, here they are:

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  • Three stage filtration (washable pre-filter, HEPA H13, and activated Carbon)
  • Removes 99.97% of airborne particles down to 0.3 microns
  • Whisper-quiet operation
  • Convenient, one-touch Night mode button to set to low speed and turn off all lighting
  • Independent button for the brightness of the light (3 settings + light off)
  • A great value for the price (MSRP $88.95)
  • At the highest speed, it can filter all the air in a 300 square foot room about 3 times per hour


  • Pre-filter is a little lightweight.  While it does dry fast when washed, I think it would be a bit better if had a more heft
  • Strong plastic smell out of the box, but this passes fairly quickly
  • Louder than the claimed 24 dB, but still very quiet


Well-packed Okaysou AirMic4S

The Okaysou AirMics4S is a medical-grade air purifier suitable for mid-sized rooms. If you have a room over 350 square feet, you should consider going with a larger model if you want to filter the air quickly, or multiple filters placed in a couple zones. The filter was packed well for shipping with an outer and inner box plus fitted styrofoam on the top and bottom to keep it centered and immobile.

The AirMic4S is light and easy to move, so it is quite possible to place the filter where it is most needed. For example, I usually keep mine near the front door and wall furnace, so it can filter pollen and burning-dust odor near the primary source. On the other hand, I move it to the kitchen if I am cooking something likely to produce a lot of smoke…or those not-so-rare occasions when I accidentally burn something.

Multiple Filter Options

The filter is a 3 stage filter consisting of a pre-filter for large materials, a true HEPA filter for small particles, and finally an activated carbon stage for removing odors. The AirMic4S comes with the Pet Filter as standard. However, one of the features I really love about this brand is the option to choose from multiple filter types based on your individual needs. In addition to the Pet Filter, you can order filters specialized for Germ Defense, Toxin absorber, and Odor Remover.


Okaysou AirMic4S low-speed, max-light
Low-speed light-on
Okaysou AirMic4S Night mode
Night mode

The controls are very intuitive and I really appreciate the independent lighting and fan controls. The blue light has three brightness settings plus the option to turn the light off. This is great when you are watching a movie in the dark, but want the filter to still be running. If you just want to meditate in the dark, the blue light and the soft white noise of the filter provide a soothing focal point. The night mode button will set the fan speed to the lowest setting and turn off all running lights.

Filter Test

Disassembled Okaysou AirMic4S
Disassembled AirMic4S

My apartment is divided by a wall with one door into two main rooms of roughly 200 square feet each. There is a wall furnace passing through both sides of the wall. As we all know, one of the first signs the weather has turned cold is the stench of burning dust the first time you turn on the heater. So, for my initial test, I fired up the heater for the first time in several months to stink up the house.

The air purifier was in the living room which is slightly larger (225 sq ft vs about 175 sq ft in the bedroom). I kept the bedroom door shut with the AirMic4S on full speed in the living room. I setup a chair outside the front door (neutral odor) and checked inside the living room every 5 minutes. Each time I made sure to open and close the front door quickly.

After only 15 minutes, I could barely detect the burnt-dust odor and after 20 minutes I could no longer detect any smell in the living room. However, I continued checking my bedroom every 5 minutes after the living room was neutral. The room odor was not back to neutral until about 40 to 45 minutes.

So, next time you fire up the heater for the first time of the year, save yourself from the unpleasant odor of burning dust. Just turn on the furnace and set your air purifier on full blast and then go for a 20 – 30 minute walk!

Noise Test

I have a simple sound meter (this one) that I used to test the sound output. I generally measured the sound at the lowest and highest setting + Night mode. I took measurements with the meter right on top of the filter (not exactly a “fair” measurement) as well as about 5 feet away on the couch where I like to read. Note that just the general background noise from the couch position with the filter off was about 40 dB (silent other than the quiet hiss of the furnace’s pilot light).

For the lowest speed, the reading on top of the fan was about 45 dB while from the couch it was was about 41.2 dB. At the highest speed it was almost 60 dB right on top of the fan, but still only 45 dB on the couch. Lastly for the Night mode, it was about 44 dB on top of the fan and only sound 40.4 dB on the couch.

While this doesn’t match the claimed 25 dB, the filter is still super quiet and bear in mind that my background noise sort of set a floor of 40 dB. I tried whispering with the sound meter at arms length and this still came in at around 45 dB, with quiet talking at around 55 dB.

After using this filter for a couple months, I can say that I have had it on while watching TV and movies or quietly reading at night, and it is quiet enough that it just fades into the background.

Maintenance Overview

Okaysou AirMic4S bottom view
AirMic4S Bottom view

You can access the filter for cleaning or replacement by unplugging the filter and turning it upside down. As you can see in the photo, no special tools are required. The built-in hand-grip is large and easy to turn without much force, so you can rest easy if you suffer from arthritis. There is an arrow on the filter cover, so you just twist counter-clockwise to unlock. To replace the cover, point the arrow at the unlocked position to reseat the cover and then twist clockwise to lock the cover (closed padlock icon on the purifier frame).

Okaysou AirMic4S bottom cover removed
AirMic4S Cover Removed
Okaysou AirMic4S Filter Removed
AirMic4S Filter removed

Once you remove the filter, the cavity is large and easy to clean with a slightly damp cloth. Remember to always unplug first and always allow all parts of the filter to dry completely before reassembling. If you have a new filter, you can remove any plastic, center it in the cavity, replace the cover and you are done.

Washing the Pre-Filter

The pre-filter is designed to prevent large particles from clogging the filter and lowering it’s effectiveness. At first glance, you may not notice the washable pre-filter. However, the pre-filter fits around the main filter similar to a lady’s stocking. See the following picture showing the pre-filter partially removed.

Okaysou AirMic4S pre-filter view
AirMic4S Pre-filter view

To remove the pre-filter, gently stretch it over the black plastic lip of the filter housing in small sections. Continue around the circle until the pre-filter is over the edge on all sides. Then gently pull it off. Wash it by hand with water or a mild detergent and allow it to completely dry before carefully sliding it back over the filter.

Ordering Info and Discount Codes

You can order the AirMic4S from Amazon via the links above. However, it is a popular product and could be out of stock, so you can also order directly from the manufacturer right here (enter code “save10” for 10% off air purifiers): Okaysou AirMic4S

You can also checkout Okaysou’s FAQs or order replacement filters. If you don’t want to have to figure out which filter to reorder every time, they also have a subscription service to have filters mailed to you at regular intervals.

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