How to Clean Air Purifier Filters: Complete Maintenance Guide

Key Takeaways

• Regular cleaning extends your air purifier's lifespan by 2-3 years and maintains optimal performance

• Pre-filters need cleaning every 2-4 weeks, whilst HEPA filters require replacement every 12 months

• Proper maintenance reduces energy consumption by up to 30% and improves air quality

• Most filters cannot be washed – knowing which type you have prevents costly damage

• Coway air purifiers feature indicator lights that alert you when maintenance is needed

Why You Must Clean Air Purifier Regularly

Your air purifier works tirelessly to trap dust, allergens, pet dander, and pollutants from your indoor air. However, without regular maintenance, these collected particles can actually reduce the unit's efficiency by up to 50% within just a few months. I've seen households where neglected air purifiers consumed 40% more electricity whilst delivering significantly less clean air—a double loss for both health and wallet.

The truth is that air purifier maintenance isn't just about keeping your device running; it's about ensuring your family breathes the cleanest air possible. A properly maintained air purifier can remove 99.97% of airborne particles, whilst a dirty one might only capture 60-70% of contaminants, essentially turning your investment into an expensive fan.

According to research from the UK Health Security Agency, properly maintained portable air purifiers can reduce PM2.5 concentrations by between 22.6% and 92% compared to controls. The connection is clear: maintenance directly impacts health outcomes.

Understanding Your Air Purifier's Components

Before diving into how to clean an air purifier, you need to understand what you're working with. Most air purifiers contain multiple filtration stages, each requiring different care approaches.

Pre-Filter (Washable)

This outer layer captures large particles like hair, dust, and lint. In my experience maintaining air purifiers across different environments, pre-filters in homes with pets accumulate visible debris within 10-14 days, whilst pet-free homes see buildup after 3-4 weeks.

HEPA Filter (Usually Non-Washable)

The heart of your air purification system, HEPA filters trap microscopic particles down to 0.3 microns. These filters have a specific lifespan and attempting to clean them with water typically destroys their delicate structure. When you notice airflow reduction or your Coway's filter indicator light activates, it's time to replace rather than clean.

Activated Carbon Filter

Responsible for odour removal and VOC absorption, carbon filters lose effectiveness over time as their porous structure becomes saturated. These are generally non-washable and require periodic replacement.

Exterior Housing and Sensors

Often overlooked, dust accumulation on air quality sensors can cause inaccurate readings, making your purifier work harder than necessary or not respond appropriately to air quality changes.

How Often Should You Clean Your Air Purifier?

The frequency of air purifier cleaning depends on several factors: usage hours, air quality in your area, presence of pets, and whether anyone in your household smokes. Here's a realistic maintenance schedule based on practical experience:

Important Note: These are general guidelines. Your Coway air purifier features intelligent indicators that monitor filter condition in real-time, providing more accurate timing for your specific usage patterns.

Research from University College London on portable air purifiers used in European homes (London, Eindhoven, and Helsinki) found that actual usage patterns significantly affect filter life, making manufacturer indicators more reliable than fixed schedules.

Which Filter Can You Wash?

This is perhaps the most common question I encounter, and the answer requires nuance: it depends entirely on the filter type. Washing the wrong filter type can cost you hundreds in replacements.

Washable vs. Non-Washable Filters

Washable Filters (Safe to Clean):

• Pre-filters and preliminary screens

• Some foam-based filters

• Permanent electrostatic filters

• Metal mesh filters

Non-Washable Filters (Replace Only):

• HEPA filters

• Most activated carbon filters

• Combination HEPA-carbon filters

• Antimicrobial treated filters

The Truth About Cleaning HEPA Filters

Despite numerous online claims, you cannot effectively clean HEPA filters. Here's why: HEPA filters work through a complex process involving interception, impaction, and diffusion. Their microscopic fibre structure creates a maze that traps particles. Water, vacuum cleaning, or compressed air damages this delicate structure, creating gaps that allow particles to pass through, essentially rendering your filter useless whilst appearing clean.

According to European standards (EN 1822), HEPA filters must remove at least 99.95% of particles with a diameter of 0.3 micrometres. "Cleaned" HEPA filters lose this efficiency, showing only 60-75% effectiveness compared to their original particle capture rate.

The money saved by attempting to clean a HEPA filter is quickly lost through reduced air quality and potential health impacts.

When your Coway's filter indicator signals replacement time, trust it. The system monitors airflow resistance and accumulated operating hours to calculate actual filter condition. You can find genuine replacement filters designed for your specific model in Coway's filter collection, ensuring perfect compatibility and maintained warranty coverage.

Step-by-Step: How to Clean an Air Purifier Filter

Let me walk you through the complete cleaning process I've refined through maintaining multiple Coway units. This method works for most air purifier brands with minor variations.

Before starting any maintenance:

• Turn off and unplug your air purifier completely—never attempt cleaning whilst it's powered on

• Move the unit to a well-ventilated area or outdoors if possible, as trapped dust will be released

• Gather your supplies: vacuum with brush attachment, microfibre cloths, mild washing-up liquid, and a soft brush

• Have a bin bag ready for any disposable filters that need replacement

Cleaning the Pre-Filter

The pre-filter is the workhorse of your filtration system and the component you'll clean most frequently. Here's my proven method:

Vacuum Method (Quick Maintenance)

Start by carefully removing the front panel of your air purifier. On Coway Airmega models, this typically involves releasing clips or sliding the panel upward. Once exposed, use your vacuum's brush attachment on low-to-medium suction to remove surface debris from both sides of the pre-filter. Work in overlapping horizontal strokes, then vertical ones to ensure thorough coverage.

This method works well for bi-weekly maintenance when the filter isn't heavily soiled. I use this approach about 75% of the time, and it takes less than five minutes.

Deep Cleaning Method (Monthly)

When your pre-filter shows visible grime or your vacuum isn't removing embedded particles effectively, it's time for a thorough wash. Remove the pre-filter completely from the unit and take it to your sink or bath.

Run lukewarm water over the filter, using gentle pressure from a handheld showerhead if available. Add a few drops of mild washing-up liquid (avoid harsh chemicals or detergents) and gently work it through the mesh using your fingers. For stubborn spots, a soft-bristled brush works well, but avoid aggressive scrubbing that could damage the mesh.

Rinse thoroughly until the water runs clear and no soap residue remains. This step is critical—soap residue can create unpleasant odours when the filter dries and the unit operates.

The Drying Process: Don't Skip This

Here's where many people make mistakes. Never reinstall a damp pre-filter. Moisture trapped in your air purifier creates an ideal environment for mould and bacteria growth—exactly what you're trying to eliminate from your air.

Shake off excess water and place the filter on a clean, dry towel. Air dry completely in a well-ventilated area, which typically takes 24 hours. I usually clean my pre-filter in the evening and let it dry overnight and through the next day. If you're in a humid climate, placing it near a dehumidifier or fan speeds up the process.

For Coway users: Keep a backup Max2 filter set on hand so you can swap immediately whilst the other filter dries—this prevents any interruption in air purification.

Cleaning the Exterior and Sensors

Whilst your pre-filter dries, tackle the rest of your unit:

Exterior Housing

Wipe down all exterior surfaces with a slightly damp microfibre cloth. Pay special attention to air intake grilles and outlet vents where dust accumulates. For stubborn spots, use a mild all-purpose cleaner, but avoid spraying directly onto the unit—spray your cloth instead to prevent liquid from entering internal components.

Air Quality Sensors

This often-overlooked step significantly impacts performance. Coway purifiers and most modern models include particle sensors that detect air quality and adjust fan speed accordingly. When these sensors become dusty, they provide inaccurate readings and may cause your purifier to underperform.

Locate your sensor opening (usually marked on your unit or indicated in your manual). Use a cotton bud slightly dampened with rubbing alcohol to gently clean the sensor lens and chamber. In my experience, this immediately improves the responsiveness of Coway's real-time air quality indicator.

HEPA and Carbon Filter Inspection

Whilst you can't wash these filters, regular inspection helps you determine when replacement is necessary. Remove your HEPA and carbon filters and examine them:

• Check for visible discolouration or heavy dust accumulation

• Note any unusual odours emanating from the carbon filter

• Verify the filter structure remains intact with no tears or damage

• Compare against a new filter if possible

Can you clean an air purifier filter? Only the pre-filter. HEPA and carbon filters lose their effectiveness when exposed to water and must be replaced. Some people attempt to vacuum HEPA filters, but this often damages the delicate pleated media. Instead, follow manufacturer replacement guidelines.

For Coway Airmega Mighty users, authentic replacement filters ensure continued peak performance with perfectly fitted components designed specifically for your model.

Coway Air Purifier Filter Cleaning and Change

Coway air purifiers incorporate user-friendly maintenance features that simplify the cleaning process. Understanding these specific functions helps you maximise your unit's performance.

Understanding Coway Filter Indicators

Coway units feature intelligent monitoring systems with coloured indicators:

• Blue/Green: Filters operating normally

• Purple/Orange: Pre-filter cleaning recommended

• Red: Filter replacement required

When you see the filter indicator light activate, don't panic—this is normal after the designated operating hours. For most Coway models, the pre-filter indicator appears after approximately 2-4 weeks of continuous use, whilst the main filter indicator activates after 12 months.

Performing a Coway Filter Clean

After cleaning your pre-filter and reinstalling it, you'll need to reset the indicator. Press and hold the "Filter Reset" button (usually marked with a circular arrow icon) for 3-5 seconds until you hear a beep or see the indicator light turn off. This resets the timer and allows accurate tracking for the next maintenance cycle.

Coway Filter Change Process

When it's time for the Coway filter change, replacement takes just minutes. Turn off and unplug the unit, remove the front cover, and extract the old filter by pulling the designated tab. Before installing the new filter, note the airflow direction arrows—installing filters backward significantly reduces efficiency.

For Coway's popular Airmega Mighty model, you'll need the Airmega Mighty 200M Max2 Filter or the Airmega Mighty 200M Green HEPA Filter, depending on your preference. The Max2 filter combines HEPA and carbon filtration in one convenient package, whilst the Green HEPA option provides standard filtration with environmental considerations.

After installation, run your purifier for 5-10 minutes to ensure proper airflow, and reset the filter indicator to start fresh tracking.

Common Air Purifier Maintenance Mistakes to Avoid

Throughout my experience, I've observed recurring mistakes that reduce air purifier effectiveness or cause premature failure. Learning from these can save you significant money and frustration.

Mistake #1: Using Water on Non-Washable Filters

The most expensive mistake. HEPA and carbon filters deteriorate rapidly when exposed to moisture. If you accidentally get these filters wet, they must be replaced—they cannot be dried and restored to effectiveness.

Mistake #2: Reinstalling Damp Filters

Even washable pre-filters need complete drying before reinstallation. I once diagnosed a "broken" air purifier that was simply suffering from mould growth in a reinstalled damp filter. The smell was terrible, and the mould spores were being circulated into the air—the opposite of the purifier's purpose.

Mistake #3: Ignoring the Pre-Filter

Many users focus exclusively on HEPA filter replacement whilst neglecting the pre-filter. A clogged pre-filter forces your HEPA filter to work harder and reduces overall airflow by up to 40%, making your entire system less effective.

Mistake #4: Using Harsh Cleaning Chemicals

Strongly scented cleaners, bleach, or abrasive chemicals leave residues that can be released into your air. They can also damage filter materials and sensor coatings. Stick with mild, fragrance-free soap and water for washable components.

Mistake #5: Delaying Filter Replacement

Operating your air purifier with exhausted filters reduces effectiveness and can strain the motor. When replacement indicators activate, plan to change filters within 2-4 weeks. The captured particles on saturated filters can become breeding grounds for bacteria and mould, actually reducing your indoor air quality.

Maximising Your Air Purifier's Lifespan

Beyond regular cleaning, several practices significantly extend your air purifier's operational life and maintain peak performance.

Optimal Placement Strategy

Position your air purifier away from corners and walls, allowing at least 30-45 cm (12-18 inches) of clearance on all sides. This ensures unrestricted airflow and reduces dust accumulation. I've found that central room placement improves coverage by 30-40% compared to corner positioning.

Avoid placing units near curtains, which can obstruct vents and introduce additional lint. Keep purifiers away from moisture sources like humidifiers or bathrooms to prevent filter damage.

Pre-Cleaning Your Space

Before running your air purifier after extended shutdown periods, dust and hoover your room first. This removes settled surface dust, preventing your filters from handling excessive particle loads during startup. This simple step can extend filter life by 15-20%.

Smart Usage Patterns

Run your air purifier continuously on auto mode rather than turning it on and off repeatedly. Modern units like Coway's Airmega series adjust fan speeds based on actual air quality, consuming minimal energy during clean-air periods whilst responding quickly to pollution spikes. Constant cycling actually wastes more energy and provides less consistent air quality.

Seasonal Maintenance Adjustments

Increase cleaning frequency during high-pollen seasons (spring and autumn) and winter months when windows stay closed and indoor air recirculates more. During summer, if you frequently open windows, your pre-filter will accumulate more outdoor particles and require more frequent attention.

According to UK Building Regulations Approved Document F, proper ventilation combined with air purification provides the best indoor air quality outcomes, particularly during periods of limited natural ventilation.

After Cleaning Issues Troubleshooting

Even with proper maintenance, you might encounter performance concerns. Here's how to diagnose and resolve common issues before assuming you need repairs.

Reduced Airflow: Check the pre-filter first—90% of airflow issues stem from clogged pre-filters. Clean or replace as needed. If airflow remains weak, verify that no objects obstruct vents and that filters are installed correctly with arrows pointing in the proper direction.

Persistent Odours: If your purifier develops musty smells, you likely have moisture issues. Remove and thoroughly dry all washable filters. If odours persist, the carbon filter may be saturated and require replacement. Remember, carbon filters absorb rather than filter odours, so they have finite capacity.

Unusual Noises: Rattling or buzzing often indicates loose components. Verify that all filters are properly seated and the front cover is secured. Increased fan noise might mean filters are clogged, increasing resistance and forcing the motor to work harder.

Inconsistent Auto Mode: Clean the air quality sensor. Dust accumulation prevents accurate readings, causing erratic fan speed changes. A clean sensor ensures your purifier responds appropriately to actual air quality conditions.

Conclusion: Clean Air Starts With Clean Filters

Proper air purifier maintenance represents a small investment of time that pays enormous dividends in air quality, device longevity, and cost savings. By following the cleaning schedules and techniques outlined in this guide, you'll ensure your air purifier operates at peak efficiency, delivering the clean, healthy air your family deserves.

Remember that regular pre-filter cleaning, timely filter replacement, and consistent exterior maintenance form the foundation of effective air purification. When you see your Coway's filter indicators activate, treat them as helpful reminders rather than inconveniences—they're protecting both your health and your investment.

Keep your replacement filters on hand by ordering from Coway's filter collection, ensuring you're never caught without the proper components when maintenance time arrives. Genuine filters maintain your warranty coverage and guarantee optimal compatibility with your specific model.

Your clean air journey doesn't end with purchase—it continues with consistent, proper maintenance. Start implementing these practices today, and breathe easier knowing you're maximising your air purifier's potential.

Frequently Asked Questions About Air Purifier Maintenance

How often should I clean my air purifier?

Clean washable pre-filters every 2-4 weeks depending on usage and environment. Wipe exterior surfaces weekly, clean sensors monthly, and replace HEPA filters annually. Pet owners should increase all frequencies by 50%.

Can I use a hoover to clean HEPA filters?

No. Whilst hoovering might remove surface dust, it cannot restore HEPA filter effectiveness and may damage the delicate fibre structure. HEPA filters must be replaced, not cleaned.

Why does my air purifier smell after cleaning?

If you washed components with water, ensure everything is completely dry before reassembly. Damp filters quickly develop musty odours from bacterial or mould growth. If the smell persists after thorough drying, replace the carbon filter.

How do I know when to replace filters vs. clean them?

Pre-filters are washable and should be cleaned regularly. HEPA and carbon filters require replacement based on your unit's indicator lights or after 6-12 months of use. When in doubt, refer to your Coway model's specific recommendations.

What happens if I don't maintain my air purifier?

Neglected air purifiers lose effectiveness rapidly. Within 3-6 months without maintenance, efficiency drops to 50-60% of original performance. Energy consumption increases, motor strain leads to premature failure, and your air quality suffers—defeating the entire purpose of owning an air purifier.

Can I wash activated carbon filters?

No. Water damages carbon's porous structure and eliminates its absorption capacity. Carbon filters must be replaced when saturated, typically every 6-12 months depending on odour and VOC levels in your environment.

How long do Coway filters actually last?

With proper maintenance, Coway pre-filters last indefinitely with regular cleaning. HEPA filters typically last 12 months in normal conditions, whilst carbon filters need replacement every 6-12 months. The built-in indicators provide accurate timing based on your specific usage patterns.

 

---

 

References

This article has been thoroughly researched and draws from peer-reviewed research, UK government health agencies, European standards organisations, and authoritative building regulations.

UK Government and Health Sources

1. UK Health Security Agency. (2021). Portable air purification: Review of impacts on indoor air quality and health. Science of the Total Environment, 766, 142585. https://researchportal.ukhsa.gov.uk/en/publications/portable-air-purification-review-of-impacts-on-indoor-air-quality
   

2. Which? UK. (2024). Best air purifiers 2025: How to buy the best air purifier. Consumer testing and maintenance guidelines. https://www.which.co.uk/reviews/air-purifiers/
   

European Research and Standards

3. European Committee for Standardization (CEN). EN 1822: High efficiency air filters (EPA, HEPA and ULPA). European standard for filter classification and testing.
   

4. University College London, Bartlett School for Environment, Energy and Resources. (2022). Why do people use portable air purifiers? Evidence from occupant surveys and air quality monitoring in homes in three European cities. Building Research & Information, 50(2), 213-229. https://www.tandfonline.com/doi/full/10.1080/09613218.2021.2001303
   

5. European Commission. (2008). Indoor Air Quality - Scientific Committee on Health and Environmental Risks (SCHER). Opinion on risk assessment on indoor air quality. https://ec.europa.eu/health/opinions/en/indoor-air-pollution/index.htm
   

Peer-Reviewed Research

6. Cheek, E., Guercio, V., Shrubsole, C., & Dimitroulopoulou, S. (2021). Portable air purification: Review of impacts on indoor air quality and health. Science of the Total Environment, 766, 142585. https://www.sciencedirect.com/science/article/abs/pii/S0048969720361143
   

7. Barn, P., et al. (2023). Real-world effectiveness of portable air cleaners in reducing home particulate matter concentrations. Aerosol and Air Quality Research, 23(8). https://aaqr.org/articles/aaqr-23-08-oa-0202
   

8. Smart Air UK. (2024). The evidence shows that air purifiers help with infection prevention and control. Evidence compilation on air purifier effectiveness. https://smartairfilters.com/uk/en/purifier-evidence/
   

9. Fermo, P., et al. (2021). Improving indoor air quality through an air purifier able to reduce aerosol particulate matter (PM) and volatile organic compounds (VOCs): Experimental results. Environmental Research, 197, 111131. https://www.sciencedirect.com/science/article/abs/pii/S0013935121004254
   

Technical Standards and Guidelines

10. British Standards Institution. BS EN ISO 29463: High-efficiency filters and filter media for removing particles from air. Filter testing and performance standards.
    

11. World Health Organization Regional Office for Europe. (2010). WHO Guidelines for Indoor Air Quality: Selected Pollutants. https://www.ncbi.nlm.nih.gov/books/NBK138700/
    

12. UK Air Pollution. (2024). Indoor air quality guidance and air purifier maintenance. https://ukairpollution.com/
    

13. Airflow Developments Ltd. Guide to Indoor Air Quality (IAQ) standards in the UK. https://www.airflow.com/about-us/blog/article?article_id=61
    

Building Standards

14. Health and Safety Executive (HSE). Ventilation in the workplace. Guidance on maintaining healthy indoor environments. https://www.hse.gov.uk/ventilation/
    

15. Installer Online. (2024). Indoor air quality legislation in the UK - What installers need to know. https://www.installeronline.co.uk/green-energy/indoor-air-quality-legislation-in-the-uk-what-installers-need-to-know/