Descrizione
An air purifier is a fan in a box with a filter in front of it. Everything the machine does well or badly comes down to that filter, and the filter is the part owners replace least often and think about least. The Fourth Pro is a direct replacement cartridge for the Xiaomi Mi Air Purifier 4 Pro, built from activated carbon and HEPA media in the same 226 by 226 by 360 millimetre form factor, so it seats into the housing without modification and without an adapter ring.
The green variant is tuned for formaldehyde rather than dust alone, which is a distinction worth understanding. Standard HEPA media catches particles: PM2.5, pollen, pet dander, mould spores. It does not catch formaldehyde, benzene or the volatile organic compounds that off-gas from new furniture, fresh paint and laminate flooring, because those are gases and pass straight through a particle filter. The activated carbon layer is what adsorbs them, and the quantity and grade of that carbon is the difference between a filter that removes odours and one that actually reduces VOC load in a newly decorated room.
The rated clean air delivery rate is 398 cubic metres per hour, which is the figure that matters when you size the machine against a room rather than against a marketing claim. In practice that is a living room or an open plan kitchen of thirty to fifty square metres running at a mid fan speed, and it means the filter is not the bottleneck in a correctly sized installation. The cartridge fits the 4 Pro body only, so check the model number before ordering, since the 4 and 4 Lite use different housings.
Replacement interval depends on use, not on a calendar. A filter running continuously in a city flat with a window onto a main road will load faster than one in a rural bedroom used at night, and the machine's own filter-life indicator is the reliable signal. When airflow drops audibly at the same fan setting, or when the cartridge has visibly greyed across the pleats, the media is done regardless of what the percentage says.
Clean air is not a feature you switch on. It is a filter you remember to change.
Key Features
- Direct fit for the 4 Pro 226 by 226 by 360 millimetres, seating into the Mi Air Purifier 4 Pro housing without adapters or trimming.
- Activated carbon plus HEPA Two media in one cartridge, particle capture and gas adsorption in the same airflow path.
- Green variant for formaldehyde Tuned for new-build and renovation VOCs rather than dust alone, which is what most replacement filters ignore.
- 398 cubic metres per hour CADR Enough throughput for a living room or open plan kitchen without the filter becoming the restriction.
- PM2.5, pollen and dander The particle side of the job, which is what shows up as the visible grey line across the pleats over time.
- Bacteria and mould spore capture HEPA media traps spores rather than recirculating them, useful in damp rooms and basements.
- Odour reduction Carbon adsorbs cooking smells, pet odour and tobacco smoke rather than masking them.
- Sealed cartridge construction One unit, no loose carbon to spill, no separate pre-filter to remember.
Technical Specifications
- Compatible model: Xiaomi Mi Air Purifier 4 Pro
- Product type: Air purifier replacement filter cartridge
- Dimensions: 226 x 226 x 360 millimetres
- Media: Activated carbon and HEPA
- Variant: Green, formaldehyde-focused
- CADR: 398 cubic metres per hour
- Targets: PM2.5, dust, pollen, allergens, bacteria, formaldehyde
- Housing: Sealed cartridge, drop-in replacement
- Brand: Filterhualv
- Quantity: One cartridge
- Care: Vacuum the outer face monthly, replace when airflow drops
- Disposal: Household waste, media is not hazardous
Where It Belongs
This belongs in a bedroom, a living room, a home office or a rented flat where the windows face a road. It suits the owner of a 4 Pro who has reached the filter-change prompt and does not want to order a cartridge from overseas and wait three weeks, and it suits anyone moving into a newly renovated property where formaldehyde from new joinery and paint is the real concern rather than pollen. It is also the sensible spare to keep in a cupboard, so a filter change does not mean a week of reduced airflow.
Frequently Asked Questions
Q: Will this fit the standard Xiaomi 4?
A: No. This cartridge is shaped for the 4 Pro. The 4 and the 4 Lite use different housings and different filter part numbers, so check the model printed on the back of your machine before ordering.
Q: How often should it be replaced?
A: Every six to twelve months in typical domestic use. The machine's filter-life indicator is the guide, but audible airflow loss at the same fan setting is the more honest signal that the media is loaded.
Q: What is the difference between the colour variants?
A: Blue is the standard particle filter, green adds formaldehyde removal for new decoration, and purple targets sterilisation and anti-mould. Green is the one to choose if the room has new furniture, paint or flooring.
Q: Does it remove cooking smells?
A: Partially, and better than a particle-only filter, because the carbon layer adsorbs odours. For heavy kitchen use, run the purifier on a higher fan speed during cooking rather than expecting the filter to clear a room afterwards.
Q: Can I vacuum the filter instead of replacing it?
A: You can vacuum the outer face monthly to remove loose dust, and that extends service life. It does not restore the carbon, which is consumed by the gases it adsorbs, so vacuuming delays replacement rather than replacing it.
Q: Is it a genuine Xiaomi part?
A: It is a Filterhualv cartridge made to the 4 Pro specification, not a Xiaomi-branded part. It fits and performs to the same dimensions and CADR rating at a lower price than the branded cartridge.
Q: Does it come with a pre-filter?
A: No separate pre-filter is included. The 4 Pro has its own washable outer mesh, which is the part you rinse, and this cartridge sits behind it.
The EastSupplier Promise
Every unit ships from inspected stock held by our own team, not from a blind dropship queue. Orders placed before 3pm warehouse time leave the same working day, and each parcel carries a tracking number you can follow from dispatch to doorstep. If a unit arrives damaged or does not match this listing, we replace or refund it inside 30 days.
- Stock checked daily: the inventory figure on this page is live, not a placeholder.
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- No surprise fees: the price you see is the price at checkout.
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