How filterless air purifier works
As the name implied, filterless air cleaner will purify the air without relying on any mechanical filter. Depends on the technology, it can cover a wide range of indoor pollutants like a normal HEPA filter would. There are 5 types of air purifiers in the market, one of those is the forbidden fruit that you should never go for.
- Ionizer/ Electrostatic recipitator – Electrostatically charge and release negative ions to merge with positive ions particles. The merge particles would fall due to the increased weight and settle down in the purifier. There are slight differences between ionizer and electrostatic precipitator. The former is usually part of a HEPA air purifier filtration. The later is a standalone unit that comes with a collector plate to collect the fall particles.
- Thermodynamic sterilization – aka Airfree air purifier. Similar concept as boiling water that kills 99.9% of microorganisms and germs through heat. The sterilization process end with only normal temperature air released back out.
- Hybrid – The main filtration must be a permanent filter or technology that is every green. While the supporting filters like carbon filter can be washable or replaceable. This enables the air purifier to work even if the rest of the filtration is worn out. Honeywell AirGenius 5 is a good example.
- Ultraviolet UV cleaner – A conversational inclusion in the list as light bulb still has a usage lifespan. Uses UV-C/ ultraviolet from a light bulb to remove bacteria and viruses. The allergens are obliterated inside thus no cleaning ever needed. Modern UVGI cleaner comes together with ionizer which we have touched on earlier.
- Ozone generator – This is the forbidden one we talked about. Ozone generator works through the process of oxidation. It split oxygen molecules (O2) into single atoms, eliminating any contaminants in between. The single atoms with merge with other oxygen molecules to form ozone (O3). Ozone generator is effective against odor, uses no filter but is harmful to our body. Inhaling to ozone can lead to many side effects and respiratory problems.
Who is this for?Anyone from that needs clean air free from germs, smoke, and allergens. Busy parents or bachelor that do not need to be tied down with another home appliances. An asthmatic or hyperallergic person that is constantly sick. Newborn, baby and children would greatly appreciate it.
Honeywell AirGenius 5 is no doubt the best air purifier with permanent filter. It is well-designed, comes with 6 pre-set timer, and a cool electronic filter gauge. It also offers solid airflow performance without the hassle filter change. There is also a highly adjustable 5 (Yes 5) selectable cleaning mode (SLEEP, GERM, GENERAL, ALLERGEN, and MAX Cleaning Power).
Powered by the ifD technology that is only available in selected Honeywell models. This hybrid model comes with 3 stage filtration that is unusual for an air purifier with a permanent filter. The Permanent QuietClean ifD filter can eliminate 99.9% of the allergens as small as 0.3 microns. Even more efficient than a True HEPA filter. Adding a negative ionizer and a permanent pre-filter, everything in AirGenius 5 is either washable or reusable.
- Zero annual filter replacement cost.
- Wide 250 sq. ft. purifying coverage.
- ifD permanent filter that can wash and reuse.
- 5 highly selectable speed plus 7 preset timers.
- ifD permanent filter is more for non-gas particles. You will need to opt for the odor pre-filter upgrade.
- You will need to regularly clean the washable filter.
Fancy AirGenius 5 but would prefer something cheaper? In comes Honeywell AirGenius 4 True Allergen Remover. This is the exact replica air purifier with a permanent filter that is also washable. Even from the exterior design, everything looks identical bar the 4 fan speed (1 less) and less pre-set timer. Airflow performance-wise, you'll get exactly the same thing as AirGenius 5. not bad at all.
As for the filtration, you gain the same patented QuietClean ifD technology that removes up to 99.9% of allergens as small as 0.3 microns. A proven technology that will save you a lot of time and money finding the replacement filter. The washable pre-filter that can be reused over and over time. You can also upgrade to an odor-reducing pre-filter that captures large dust, hair, smoke, and odors! Lastly, there is an ionizer that will electrostatically charge ions for easy capturing.
- No filter replacement needed.
- Wide 250 sq. ft. purifying coverage.
- The same ifD permanent filter as AirGenius 5.
- 4 fan speed plus 3 preset timers.
- Only slightly cheaper than AirGenius 5 but with less features.
- ifD permanent filter cannot trap smoke and gas particles.
- Permanent filter requries constant cleaning to maintain its efficiency.
Airfree Lotus is an air purifier without filter in its filtration. That's right. the air purifier that will purify your air without any filters. This is done through Thermodynamic TSS Tech. Internally, it will boil up to 400°F (Yup 400°F) and only release back cool air out. Effectively killing any microorganism in the process. This includes irritants like pollen, mold, dust mites, odors, ozone, bacteria, and viruses.
There are other perks of Airfree Lotus beside not having a filter. There is no filter change or clean ever needed. It is very small, produce no ozone and even support multi-color night light. Perfect for a family that has children sleeping in their own room.
- Patented Thermodynamic TSS Purification Technology.
- No filter replacement ever needed.
- Support up to 650 sq. ft. room size.
- 10 selectable color night light.
- Completely silent operation.
- Does not capture dust or any large particles quick enough.
- To ensure consistent performance, the air purifier must be turned on all the time.
The cheapest, no fancy design, filterless air purifier listed here that cost less than 100 (after discount). Unlike the above Airfree models, there is nothing fancy about Airfree T800. It does not have a night light, has small purifying coverage, and topple easily. Why are we featuring it then? Simple. The no filter, water heating Thermodynamic TSS Technology is still here.
Airfree T800 downside is also its upside. Imagine having a super slim air purifier that can purify your air without the use of any filter. It can work silently in the background without emitting any harmful toxic. Best of all, it will kill germs, bacteria, and viruses as its big brother would. What else could you ask for more?
- Small, light and portable.
- Very cheap, around 3-4 times less than normal model.
- No filter replacement needed.
- The same Thermodynamic TSS with the exact water boiling efficiency.
- Completely silent operation.
- 180 square feet coverage is poor.
- There is also the slow purification process to contend with.
Let's get this out of my chest. Hamilton Beach TrueAir Compact Pet is not the best air purifier with a permanent filter. However, it still offers good filtration value and more importantly, is dirt cheap. So why are we putting it here? Is because it works and some people do not need all the fancy stuff. Inside the 3-stage filtration, there is a permanent, washable HEPA filter that does not require replacing. With proper cleaning, no dust, hair or pet dander will be too difficult for this pet machine.
Hamilton Beach is a washable HEPA filter air purifier that everyone could afford. This compact air cleaner is best used as tabletop lying vertically or horizontally. Do not expect anything more than that and you'll be fine. With that being said, we would still recommend you to go for any of the above filterless air purifiers.
- Permanent and washable HEPA-grade filter with a 99% capturing efficiency.
- Compact and versatile body.
- Washable pre-filter or an optional carbon zeolite filters.
- Low noise operation.
- The 140 sq. ft. purifying range might not sound too bad, but in real life, coverage is really small.
- Weak filtration and the 3 fan speed makes little differences.
- Additional features are non-existence.
Filterless is Airfree. Airfree is filterless. This is how we would describe Onix 3000. A compact air purifier without filter that kills germ silently in the background. The entires process is safe, proven, without releasing any harmful ozone. All these are achievable thanks to the Thermodynamic TSS Technology that applies the concept of boiling water. Even microscopic allergens like bacteria and viruses will not be able to stand the heat.
There's a lot of similarities between Airfree Onix 3000 with Lotus. The silent no filter purification, one-button operation, and night light. It's no HEPA air purifier but that's the beauty of it. If you don't mind the killing it softly purification, there are other mirroring models like Iris 3000, P3000 or the older P2000.
- Support up to 650 sq. ft. coverage.
- Thermodynamic TSS Technology that destroys (note: NOT capture) microorganisms.
- No filter change or maintenance every needed.
- Adjustable night light.
- Zero noise operation.
- Not super effective against dust.
- Slow purification that would take days to cover an entire room.
🏆 Honorable mention
- Bionaire/ Holmes has many zero filter air purifier that is cheap and compact. Keep in mind a lot of the models are no longer in production. Avoid those.
- Envion do carry a few iconic model that we have not reviewed (yet). Something you can ponder on.
📃 Previous holder
- Airfree P2000
- Airfree Iris 3000
- Bionaire/ Holmes Egg air purifier
2020 Best Filterless Air Purifier
|Air Purifier||Online Price (Amazon)||Filtration||Coverage||Score|
|Honeywell AirGenius 5 HFD320 Air Purifier|
|3-stage||250 sq. ft. (23 m2)||8.3|
|Honeywell AirGenius 4 HFD310 Air Purifier|
|3-stage||250 sq. ft. (23 m2)||8|
|Airfree Lotus Air Purifier|
|1-stage||650 sq. ft. (60 m2)||7.6|
|Airfree T800 Air Purifier|
|1-stage||180 sq. ft. (17 m2)||6.2|
|Hamilton Beach TrueAir Compact Pet 04384 Air Purifier|
|3-stage||140 sq. ft. (13 m2)||5.5|
|Airfree Onix 3000 Air Purifier|
|1-stage||650 sq. ft. (60 m2)||7.8|
Air Purifier Permanent Filter VS Replaceable Filter
If we are comparing apple to apple, the key differences between a permanent and replaceable filter are the filter efficiency and lifespan. E.g. permanent HEPA filter typically has an efficiency of 99% in capturing small particles as small as 2 microns. Replaceable True HEPA filter is at least 99.97% capturing efficiency at particles as small as 0.3 microns. A permanent filter does not require replacing but you will need to clean every 2-3 months to maintain its efficiency. A replaceable filter does not need to be clean but has a short lifespan that requires change once expired. There is no maintenance cost on a permanent filter as it can be reused over and over again. A replaceable filter will cost you between $50-200 annually depending on models.
Are Permanent HEPA Filters Good?
A permanent HEPA filter is cost-saving and eco-friendly because it is reusable. A permanent filter will also able to capture microscopic particles including mold, pollen, pet dander, dust mite, and germs. However, its efficiency is typically one notch below a replaceable True HEPA filter. In long-run, it might be advisable to go with a permanent HEPA filter to avoid paying the recurring cost. The total cost of 2-3 years of filter replacement can be equivalent to a brand new air purifier.
How Do You Clean A Permanent HEPA Filter?
First and foremost, check the manual if the permanent HEPA filter can be clean. If can, turn off and unplug the air purifier. Then remove the front cover and take out the permanent HEPA filter. Next, gently vacuum on a vertical stroke without applying too much pressure. If the filter is lightly discolored or yellowish, ignore as it is due to oxidization. Once done, reinsert the filter accordingly and close the front panel. Repeat the steps every 1-3 months or when the permanent HEPA filter is showing signs of slowing down.