Coway Airmega 250S review — a stylish air purifier that works

Coway is the manufacturer behind the most popular air purifier in the world, the Airmega AP-15122HH which has been the number one pick from the team at the NY TImes’ Wirecutter since 2014. 

We have tested a few of their devices in the last few years but none of them looked nearly as good as the one I’m reviewing today: the Coway Airmega 250S.

The Airmega 250S is a relatively new model that has been around since the end of 2021, and has been very well received by the press. So well received, in fact, that one reviewer referred to it as “the Wagyu Beef of Air Purifiers”…

That got me even more interested in testing its performance.

As always, we bought the Airmega 250S with our own money to experience the customer journey just as you will and remain unbiased without any special deal or connection to Coway. In this review, I will compare the Airmega 250S to the more than 100 air purifiers we have tested at HouseFresh, based on our first-hand data on air cleaning performance, sound generation, energy efficiency, real-life user experience and long-term running costs.

To find out more about how we test air purifiers, please click on this little montage image below:

The lowdown on the Coway Airmega 250S

If you don’t want to read my full review of the Coway Airmega 250S, here are the three things I like and the three things I don’t.

The best Airmega 250S feature: Retro-inspired design built with high quality materials

The 250S has been built to last and is guaranteed to look great in most rooms.

If you’re reading this review, it’s probably because you saw the 250S and thought the design was worth paying extra compared to other air purifiers from Coway. 

I’ll be honest, as soon as I unboxed this device, I became obsessed with how it looks. I am not one to care about design or aesthetics but the Airmega 250S really made me notice. And it’s not just how nice the retro-inspired design looks — from the plastic chassis to the braided cable, this thing has been made with high quality materials.

A heavy, rectangular air purifier with two on-board sensors and app connectivity

Plus, you can customize the cover of the 250S further with three unique artworks. We didn’t because it is expensive.

Weighing 20.5 lb (or 9.3 kg), the Airmega 250 S is heavier than other similarly powered air purifiers, and it is also wider than other mid-sized devices so it will take up more space on the floor. The good news is that Coway has included hand holds on each side, so it’s fairly easy to move around the house.

We bought the Airmega 250S in Warm Gray, but if you go with the Airmega 250 Art, you can upgrade the look of the device to include an artwork imprinted on the front cover. However, it will cost you an additional $50 if you buy from Coway (or an added $100 if you buy from Amazon) and you will be giving up on the app connectivity that you get with the 250S.

Something I really like is that the Airmega 250S comes with two sensors: one for particles and one for gases. This allows the 250S to run on automatic, switching to high fan speeds as needed based on the readers of the sensors.

While it has no screen at the top to see air quality levels as you would with the Philips 3000i or the Winix T810, the Airmega 250S comes with an LED bar that changes color depending on how bad the air quality is — you will also get an alert through your phone once you have setup the app.

The AQI light bar will change color from blue (good) to green (moderate) to yellow (unhealthy) to red (very unhealthy). It is easy to see and sits on top of the device, to the left of the control panel.

From left to right, you get a power button, a mode button (to switch between Sleep, Rapid and Smart), then you get a fan speed button followed by a light button (that doubles as a child lock button). Moving forward from then, you get the indicator that will alert you when it’s time to clean the pre-filter or change the main filter, which will function as a filter reset button. Lastly, you get a Wi-Fi button and indicator light.

By the way, the ‘Smart’ mode is what other manufacturers would call an auto-mode. Once you press it, the 250S will function autonomously, adjusting fan speeds based on the air quality readings and the conditions inside the room. 

Something I really like is the introduction of a ‘Rapid’ mode, which will supercharge the ‘Smart’ mode ensuring the device will hit its highest fan speed until the air quality is improved. This is something that auto-modes suck at as they usually are programmed to never hit top speed to keep sound levels and energy consumption low, but this leads to the air never being truly clean. 

The Airmega 250S comes with app connectivity through the Coway IoCare app, which is easy to use and has a clean UX without invasive ads. You can access all the controls you get on the device from the app, with the added option of scheduling routines and accessing historical air quality data.

An issue I encountered with the IoCare app is that it keeps logging me out. This is especially annoying if you don’t have the password handy. Based on the poor 1.4 out of 5 stars the app gets in the App store, it looks like I am not the only one having difficulties. But to be fair to Coway, I haven’t had any other issues with the app apart from this.

A bonded H13 HEPA filter with pelleted activated carbon

It’s great to see the inclusion of a removable pre-filter that is also washable.

With the Airmega 250S, Coway moved away from the non-bonded filters we’ve seen in the past from models such as their incredibly popular AP-15122HH or the newer Airmega 200M. 

Unlike those models, the 250S comes with an all-in-one filter they call ‘Max 2’ filter with a Green True HEPA particle filter on one side and a gas filter on the other.

According to Coway, the Green True HEPA filter is medical-grade HEPA H13. And for the gas filter, Coway went for pelleted activated carbon, which I much prefer to the carbon impregnated fabric they use for the AP-1522HH.

Bonded filters can have better performance at removing particles compared to separate filters, but once the carbon runs out, you will need to replace the whole filter — even if the HEPA filter didn’t need to be replaced.

I do like that you get the benefit of a washable pre-filter. Now this probably says more about my obsession with air purifiers, but the removable pre-filter on this unit is really high quality and slides into place beautifully:

The Airmega 250S cleared our test room in 24 minutes

This is two minutes faster than the older AP-1512HH Mighty but a full minute slower than the Airmega 200M.

We started by testing the particle removal performance of the 250S running at its highest fan speed. According to our PurpleAir Zen sensor, it needed 24 minutes to achieve PM1 zero in our 728 cubic ft. test room:

Based on the natural ventilation of our 728 cubic feet test room, we estimate that the Coway Airmega 250S has a top speed PM1 CADR of 249 cfm.

With this data in hand, we can compare the performance of the 250S to the results of other similarly-priced air purifiers running at their top speed:

As you can see from the table, air cleaning performance to cost seems fair when benchmarking with other similar powered devices. That said, you still get a much better bang for your buck with something like the AirFanta 3Pro, Vital 200S or Winix 5500-2. 

And if you are set on getting a Coway but not too fussed about it being the 250S, then you should probably look into the Airmega 200M, as it offers better particle removal performance for a cheaper price.

Louder than similar performing air purifiers

In our testing, the sound levels of the Airmega 250S ranged from 36.5 dBA to 35.7 dBA.

If an air purifier is too loud, you will find yourself turning it off eventually.

That is why we used a sound meter to measure how much sound the Coway Airmega 205S generates from 3 ft. away at each of its fan speeds:

Be aware our background noise is 35 dBA, so the 250S running at sleep mode and set to speed 1 is likely to be quieter than 36.5 dBA if you could measure sound levels in a silent room.

I also made a comparison with other devices that have similar performance:

As you can see from the table above, when running at its highest fan speed, the 250S generates as much noise as the majority of other mid-sized traditional air purifiers. However, it is clear that this device is much louder than a PC fan-powered air purifier like the Luggable XL-7 from CleanAirKits.

One of the benefits of going with a mid-to-large sized air purifier, is that you can run them at low (and quiet) fan speeds while still enjoying powerful air cleaning performance due to use of larger fans and filters. That is why we also test the particle removal speed of our air purifiers running at quiet fan speeds.

The Airmega 250S needed 64 minutes to remove all PM1 particles from the air running at speed 1 (36.5 dBA) and 30 minutes running at speed 2 (50.2 dBA). 

We can compare these results with other air purifiers running at lower fan speeds:

The Airmega 250S has only one speed (1) that meets our criteria for quiet performance, which are fan speeds that don’t generate more than 45 dBA, as this is the limit CleanAirStars sets for offices and classrooms.

We will stick to the time achieved with the lowest fan speed for our sub-45 dBA CADR calculations, which estimate that the Coway Airmega 250S has a sub-45 dBA PM1 CADR of 91 cfm.

I would like for Coway to add a fan speed in between speed 1 and speed 2 that doesn’t exceed 45 dBA, as this is a sound level that many people will have no issues hearing all day in the background.

The cost to run a Coway Airmega 250S: $224.08 per year

We look at how much the 250S will cost you in the long term, including your energy bill and filter replacement costs.

1. Electricity costs = $64.10 per year

As always, we used our energy meter to record how much energy the Airmega 250S uses when running at each fan speed and also while on standby.

If you had to leave your 250S running at its top speed 24/7, it would cost $64.10 in energy costs for a year. 

Now, I know this is an unlikely scenario as you will probably prefer having the device running at a quieter fan speed in the background, but I use this ‘worst case scenario’ to estimate the most the 250S could add to your energy bill each year.

With this calculation in mind, we can compare the annual energy costs you can expect from the 250S to other devices we have tested:

The Airmega 250S consumes around the same level of electricity as many of our top recommended air purifiers with similar performance. As the comparison with the AP-15122HH shows, the 250S has a far more efficient fan motor than the older Coway model.

2. Filter costs =  $159.98 per year

It’s not just energy costs that add to the running cost of an air purifier, you will also need to replace the filters eventually. In the case of the 250S, Coway says that you need to replace the filters every 6-12 months.

We always take the lowest estimate when calculating filter replacement costs, so we will base our estimates on filters needed to be replaced twice a year.

The recommended official filter (AP-1720-FP) costs $79.99, which means that you will need to spend $159.98 each year in filter replacements. 

We can combine that with energy costs and compare it with other similar performing air purifiers:

Due to the filters needing to be changed twice per year, the costs are higher than those models that only need changing every 12 months. In this benchmark of similar devices, the 250S ranks as the air purifier with the highest long-term running costs.

Bottom line: Should you get the Coway Airmega 250S?

For raw money-to-air-cleaning-performance, you will get a better deal with the older AP-15122HH or the newer Airmega 200M.

The Airmega 250S has excellent build quality and is beautifully designed, so it is a good option for those who are happy to spend a little more on an air purifier with smartphone connectivity that will look great while cleaning the air.

However, if you like the look of the 250S but are not keen on having yet another app on your phone, then you may want to choose the Airmega 250 instead or even the Airmega 250 Art for a snazzier look.

If you’re not convinced by the looks, then I’d say there are other mid-to-large sized air purifiers out there that will give you great air cleaning power even at quiet fan speeds for less or about the same price you’ll pay for the 250S.

A big problem with this device is the small number of fan speeds. 

While speed 1 is very quiet, air cleaning performance is not as impressive. Switching to speed 2 will improve this, but the 250S will get noisy as this fan speed goes over 50 dBA, which is louder than most people would like to have running continuously. 

It would be much better to see a fan speed in between that runs at just under 45 dBA, as we know that many people could deal with this sound level running all the time in the background.

For those wanting a powerful air purifier with excellent quiet performance, smartphone connectivity, and a design that looks as good as the Coway 250S, check out the Levoit EverestAir. 

And if you want to save some money, look into the Winix 5500-2 and the Levoit Vital 200S, both of which will give you the same level of air cleaning power for a cheaper upfront and long-term cost.

I hope my review was helpful and if you have any questions about the Coway Airmega 250S, be sure to leave them in the comments below.