Coway air purifier red light: What it means and how to fix it

DIY fixes to remove the Coway red light and get your purifier back in action.
Updated on April 15, 2024
Written by
Paul Allen
Paul was a staff writer for HouseFresh between November 2020 and May 2024. He was specialized in product recommendations and advice for smokers and apartment dwellers.

Our verdict

A red light on your Coway air purifier isn’t always a sign of a huge problem.


In most cases, it will indicate it’s time to replace your filter or even be part of the air quality feedback display. 


There are simple solutions to remedy the red light, from replacing or reinstalling the filter to ramping up fan speeds to tackle higher pollutant loads.

Coway is one of the most popular purifier brands out there. The South Korean outfit offers a range of innovative air purifiers, with the likes of the AP-1512HH (Wirecutter’s top pick since 2015 🤯) and Airmega 300 being trusted by millions of users around the world. 

But like any air purifier, they are not immune from the occasional hiccup that leaves owners scrambling for their long-lost manuals.  

One of the most common issues is the red warning light. If this appears, you can easily begin to fear the worst. But red lights are common on air purifiers and usually act as an alert to take action rather than a sign your unit has given up the ghost. 

What does the red light mean on my Coway air purifier? 

Seeing a red light appear on your air purifier could boil down to a few different reasons. Below, I’ll unpack each potential problem.

1. Your filter needs to be replaced

Coway units use mechanical filters such as HEPA and activated carbon. These work by trapping pollutants inside as dirty air passes through. Meaning that over time, they will become saturated and lose efficiency. 

Once this happens, you will see the red warning light informing you that it’s time to change your filter. 

2. There are high concentrations of airborne pollutants in the room

Some Coway air purifiers have an in-built air quality sensor that monitors indoor air pollution and relays information through a color-coded display. 

If the air is particularly dirty in your space, this will show as red. 

3. Restricted airflow due to incorrect filter placing or blocked intake

A warning light might appear if the purifier struggles to intake air from your space. 

This could occur if the ducts become clogged with large particles such as hair, lint or dust or because the filter has been incorrectly installed.

4. WiFi connectivity issues

If the WiFi light blinks, the purifier may have lost its connection to your network. 

This can unexpectedly happen from time to time and is usually a result of your router being down or the unit attempting to connect at the wrong frequency. 

8 steps to fix the Coway air purifier red light warning

Now you’ve identified the problem, here are 8 simple steps to get your purifier back to its prime.

Step 1: Increase the fan speed

If your air quality display is showing red, ramp up the power of your unit to its highest speed setting to circulate more air and reduce the amount of particles affecting your space.

After an hour or so, the color should change to display better air quality (blue/green). If not, see step 8.

Step 2: Check your internet connection

If the WiFi light is flashing red, you’ll need to reestablish your connection. First, check your router and test your internet connection on a different device. 

If everything works as it should, head to the IoCare app and see if your purifier is still paired with your phone and router. 

If it has disconnected, select “Register Product” and scan the barcode on the back of your purifier.

Next, activate the pairing mode on the purifier itself by holding the Light and WiFi buttons simultaneously for three seconds. 

You should then hear a beep and be prompted to advance on the app.

Hit ‘Next’ then create a nickname for your unit and agree to connect to WiFi, selecting your network and entering the password. The light should then become solid, indicating you’ve successfully connected your device.  

Step 3: Ensure the filters are installed properly

Ensure that it’s installed correctly, fitting snugly inside the unit with the pre-filter facing you.  

Try to gauge whether the filter has approached the end of its lifespan by gently inspecting the between the HEPA pleats. It may be time to order a replacement if it is noticeably dirty. 


New filters come in a plastic wrapper. Ensure you have removed this before installing.

Step 4: Clean your pre-filter

The pre-filter captures large particles which can restrict airflow if left to accumulate. Aim to clean the pre-filter once every two weeks to keep your purifier in tip-top shape.

To do so, remove the pre-filter from the unit and either use a vacuum cleaner to remove light particle buildup or use a mild detergent and warm water to clean a dirty pre-filter more thoroughly. 

Remember to allow the pre-filter to dry completely before reinserting it into the purifier. 

Step 5: Deep clean your air purifier

Cleaning and maintaining your purifier will clear particle build-ups and improve airflow.

While the pre-filter is drying, use this opportunity to clean the rest of the unit. Using a brush, vacuum or a slightly damp cloth, wipe down the internal fan, air outlet grill and external body of the purifier. 

Step 6: Replace your filter

Coway states that their filters last between 6-12 months, but this can vary depending on how often you use the purifier and the concentration of polluting particles in your home environment. 

If your filter has reached the end of its lifespan, start by disconnecting your unit from the power source before opening the panel to reveal the filter.

Remove and discard the old filter before replacing it, making sure to orientate the new filter correctly. 

Finally, securely refit the front panel, and you’re good to go.

Step 7: Reset the filter warning red light

After replacing your filter, it’s important to remember to reset the filter warning light. This alerts the unit that you’ve replaced the filter and resets the reminder function.

To do so, simply turn on the purifier and hold down the filter button for 5-7 seconds. 

Step 8: Clean the air sensor and adjust settings

If your air quality indicator continues to show red after prolonged use at the unit’s top speed setting, there may be dust, dirt or debris on the sensor itself. 

To clean the sensor, shut off the unit and open the sensor cover.

Using a dry cotton swab, gently brush the lens and the surrounding area to remove any particles.

If the problem persists for no clear reason, you can adjust the sensor’s sensitivity to airborne pollutants.

To select between the three sensor settings, open the IoCare app and select your unit. Hit the ‘Device Management’ tab and continue to the settings page.

Here you can select ‘Smart Mode Senstivity’ and opt for sensitive/normal/insensitive. If the unit is continually showing red, you’ll probably want to switch to insensitive to see a change. 


If your purifier isn’t WiFi compatible, don’t worry; you can still adjust the sensor manually. Check out Coway’s detailed instructions for all applicable air purifiers here.

Wrapping up

Maintaining your air purifier is vital to keeping your home a pollutant-free environment. So if an ominous red light appears, it’s handy to know how to solve the problem yourself. 

If your Coway starts to display a red warning light, work your way through this troubleshooting guide and you should be back on track to breathing clean and healthy air. If the problem persists, it’s advisable to reach out to Coway directly for more tailored technical support.  


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About the author

Paul Allen

Paul was a staff writer for HouseFresh between November 2020 and May 2024. He was specialized in product recommendations and advice for smokers and apartment dwellers.

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