Coway Airmega AP-1521HH Mighty review: Our top air purifier effortlessly clears dust, smoke, and pet dander

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My seasonal allergies, mild asthma, and two long-haired cats prompted the quest for a high-quality air purifier. While I can't control what's in the air outdoors, keeping indoor air pollutants like pollen, dust mites, and pet dander to a minimum helps keep sneezing, coughing, and sniffling at bay.

My main criteria for choosing an air purifier were effectiveness, ease of use, and noise level. Since my home doubles as my office, I needed a model that wouldn't be loud and distracting. I found what I was looking for in the Coway Airmega AP-1512HH Mighty, an air purifier designed for medium-to-large rooms.

To test the Coway's performance, I conducted air quality tests using incense in a closed room. Then, I used the air purifier for several weeks in my home, running it around the clock. The Coway was ahead of the pack among the best purifiers we've tested. Here's why we recommend the model as the top choice for busting indoor pollutants.

Set up and design

Getting the Coway Airmega AP-1512HH Mighty up and running took under five minutes. When I unboxed the air purifier, I found the manual resting at the top of the package. The unit itself was wrapped in plastic, which I removed. Then, following the manual's instructions, I popped off the front grill and removed the activated carbon and HEPA air filters (also encased in plastic) from the unit, replacing them after unpackaging was complete. The grill is easy to snap on and off, making filter changes a breeze. After that, I plugged the power cord into the unit and an electrical outlet, and it was good to go.

In addition to the carbon filter, which reduces odors such as smoke, cleaning, and pet odors, and the HEPA filter, which filters microscopic airborne particles like bacteria and viruses, the Airmega contains a washable prefilter. It prevents larger particles like dust, lint, and pet hair from clogging the other filters.

The Airmega, which comes in black or white, has five fan speed settings: low, medium, high, auto, and Eco. These settings are located on a control panel on top of the unit, and I found them easy to access and adjust. The air purifier also contains an ionizer, but we advise turning off the ionization function. That's because, according to the Environmental Protection Agency (EPA), ionizers typically produce ozone, a harmful lung irritant, as a byproduct.

The Coway is designed so that air enters the filtration system at the front of the unit rather than the back, with filtered air exiting at the top, which enables you to place the unit on top of a table or close to a wall without impairing its function. I keep mine in the corner of my bedroom and hardly notice it at all.

The Coway includes an air quality indicator light, a helpful feature that changes color as air quality improves; red signifies unhealthy VOC levels, purple means moderate VOC levels, and blue means levels are healthy. When I use a product containing fragrance in my bedroom, it kicks into higher gear.

Our review of the Coway Airmega AP-1521HH Mighty

Out of the over 30 models we tested, the Coway AirMega AP-1521HH Mighty air purifier was the fastest at removing volatile organic compounds (VOCs) and air pollutants like dust, pollen, and pet dander, making it a great choice for allergy sufferers.

Overall Ease of Use

The Coway Airmega is simple to use. I set it to Eco mode, which means it automatically turns off after 30 minutes of achieving healthy air levels and checks air quality at 30-minute intervals thereafter. You can select other modes, too, including auto, low, medium, and high, but all changes must be made manually since there's no remote or wifi connectivity. The fan will not stop in these four settings regardless of the air quality.

I placed it in my bedroom, where my two cats like to hang out. Since it's located where I sleep, I love that it operates quietly. I can turn off the air quality light at night at the touch of a button (located in the middle of the control panel). The unit can also run on one-, four-, or eight-hour timers, but I prefer leaving it on around the clock to keep the air nice and clean.

To test the unit, I let the air purifier run on Eco mode 24/7 over several weeks. Its average energy expenditure was about 0.3 kWh in 24 hours, about the same as running a 60-watt light bulb for five hours. My electricity company charges about $0.16 per KwH, so running it on Eco mode nonstop for 30 days would cost me about $1.44.

Performance

To evaluate the Coway Airmega AP-1512HH Mighty's performance, I experimented by burning incense in a 200-square-foot room with all doors and windows sealed. I used an air-quality monitor to track volatile organic compounds (VOCs) and particulate matter (PM) at 15-minute intervals.

After allowing the incense to burn for 15 minutes, I activated the air purifier's auto mode, which adjusts the fan speed according to the air quality. After two hours, I assessed the percentage of pollutants removed and the remaining VOCs and particulate matter levels.

The PM reached its highest reading (134) at the 30-minute mark. After an additional 45 minutes, the air quality was down to 32 PM, and by one hour, it was down to 8 PM. Even though the air purifier is designed for larger spaces than the one I used to test it, its ability to rapidly improve the air quality was impressive (and its performance exceeded the other models we tested).

Noise

As I mentioned above, the Coway runs quietly on most settings. On its lowest setting, my sound meter registered 41 dB (the noise level of a quiet library). In Eco mode, I often forget it's even on, and it sits quiet enough not to interrupt my sleep at night.

However, the Coway is noisy on its highest setting, registering at about 64 dB—the same as an electric toothbrush. Luckily, even if I choose auto mode, it rarely kicks into high gear unless I'm burning a candle, using cleaning products, or spraying perfume.

Maintenance

The Coway is relatively easy to maintain, but there are a lot of cleaning steps outlined in the manual to remember to keep it in top shape. Honestly, I find the process a bit cumbersome, but it's worth knowing that my air purifier works optimally. The hard part is remembering how often each step should be performed—I put a reminder in my iPhone calendar.

• Air quality sensor: Open the air quality sensor cover every two months (or sooner in dusty environments) and clean it with a soft brush or vacuum cleaner. Use a wet cotton swab to gently clean the lens, dust inlet, and dust outlet, removing excess moisture with a dry cotton swab.
• Air inlet and outlet: Clean the air inlet and outlet on top of the unit using a soft brush every two months. If dust falls into the air purifier during this process, let it run for 10 minutes on manual mode.
• Front cover and product body: Wipe down the cover (remove it first) and unit with a soft cloth every two weeks. If needed, it can be slightly wet.
• Prefilter: Depending on its contamination level, you'll need to clean the prefilter with water or a vacuum about every two to four weeks. When using water, ensure the prefilter is dry before placing it back in the unit.
• Activated carbon filter: Replace this filter every 6 months or sooner, as the filter replacement light indicates.
• HEPA air filter: This filter is replaced about once a year; just check the filter replacement light.

Filter replacements for the Coway cost about $70 a year, which is the average for the models we tested. Each pack comes with one HEPA filter and two activated carbon filters. Coway has also introduced specialized filter replacements that prioritize smoke or pet odors if you're looking to target specific concerns.

Cons to consider

The main drawback of the Coway could also be considered a pro — it doesn't come with any bells and whistles like WiFi or app connectivity (or a remote), so you have to adjust it manually. While that can be a pain, it's also easy to "set it and forget it" by choosing auto or Eco mode. Just keep in mind the sound level can be quite loud on its highest setting, so we don't recommend using that mode if you're concerned about noise.

Again, the Airmega contains an ionizer, but we advise turning off the ionization function.

What are your alternatives?

Coway offers a wide variety of air purifiers.

If you value smart features like WiFi or voice controls, Coway offers a smart edition of the Airmega Mighty. I haven't tested it, but customer reviews detail difficulty connecting to the internet and an underwhelming app.

If you're looking for a comparable option from Coway for smaller rooms, you might consider the Airmega 100, designed for rooms up to 810 square feet, While we haven't evaluated the Airmega 100, which is Coway's newest model, it's the brand's second best-selling Airmega model, according to the company and a good option for bedrooms. For extra-large spaces, there's the Airmega 400S, which serves spaces up to 3,120 square feet of coverage and is wifi-enabled. It operates quietly with low energy use but only exhibited average performance in our tests.

Among the air purifiers we tested with the best performance, the Shark NeverChange Air Purifier Max is a comparable option to the Airmega Mighty. Although the upfront cost is higher than the Coway Airmega AP-1512HH Mighty, its filter lasts up to five years, significantly reducing future costs. Another model that has consistently earned a top spot in our performance tests is the Honeywell HPA300 HEPA Air Purifier. It quietly and quickly removes air pollutants and allergens and has relatively low maintenance.

The bottom line

Consider the Coway Airmega AP-1512HH Mighty if you're seeking an effective and user-friendly air purifier for a medium-to-large environment. Its ease of use and no-frills style make it ideal for anyone who wants a cleaner environment without the fuss of smart technology.

I have definitely noticed a difference in my allergy symptoms this Fall. I'm sleeping better (no more nighttime sneezing and sniffling), and I'm more comfortable overall on high-pollen days. My seasonal allergy symptoms persisted indoors in the past, but now my home is a haven of relief.