1. UV light
UV lights on air purifiers are usually poorly implemented and the fact is that you simply don’t need to kill the germs to filter them.
Air purifiers with HEPA filters are just fine capturing germs. The germs do not need to be killed for them to be filtered out of the air.
2. Antimicrobial Filters
There’s nothing wrong with antimicrobial filters but first of all if you choose to buy a unit with an antimicrobial filter you’re limiting yourself greatly in terms of which models on the market actually have antimicrobial filters. Maybe there is a unit that is very good otherwise but it doesn’t come equipped with an antimicrobial filter. If you are limiting yourself to a unit with an antimicrobial filter now you’re missing out on a potentially great air purifier.
Furthermore units that do come equipped with the antimicrobial filters are usually exorbitantly priced. This is just a general trend that we noticed as we evaluated all air purifiers in the market and specifically looked at units that do come equipped with antimicrobial filters.
Finally again as we said for UV light, you don’t need to kill germs to filter them from the air. An air purifier equipped with a HEPA air filter is going to be able to remove germs from the air without needing to kill them first.
3. An air Quality Sensor and Accompanying Air Quality Display and Accompanying Auto Mode
The fact is that most built-in air quality sensors on air purifiers simply aren’t very good.
A good high quality air quality sensor normally runs between $200 and $300 dollars on the bottom end of the spectrum. Most air purifiers retail for at least a hundred two hundred dollars.
So for you to be able to get a high quality air quality sensor in there on top of everything else that the air purifier provides is simply not reasonable.
Now built-in air quality sensors do pick up extreme changes in particle concentration. For example, if you were to start cooking near an air purifier, the air purifier sensor will be able to pick that up.However another example might be a few pollen grains coming into the air at a particular space the air quality sensor on a regular air purifier may not be able to pick up those pollen grains.
So it’s not going to trigger a higher fan speed or be activated because it’s not sensing that small concentration of particles, and this is why we always recommend running an air purifier on the maximum fan speed possible.
That is to say the highest fan speed with a noise level that you can tolerate, because doing so is going to allow the air purifier to process new particles that may enter the air in the room as quickly as possible regardless of whether it’s air quality sensor actually picks up those new particles or not.
4.Any other Specialized Auto Modes including Eco Mode, Sleep Mode and so on and so forth
Again we recommend setting fan speed manually. These extra modes are not necessary. If you do find the air purifier to be too loud on the manual setting on a higher manual fan speed, simply select a lower fan speed. You can do so manually you don’t need to have a automatic mode set the air purifier fan speed for you.
If you do end up setting it to auto mode, let’s say you do set the air purifier to a sleep mode, the sleep mode is only going to run the air purifier and a lower fan speed. You can do so manually by simply setting the unit to a lower fan speed.
Air purifiers are not large appliances. Even the larger units are still going to be relatively small. They’re still going to be relatively light. For example, the unit we will discuss later about here, the CoWay Mighty air purifier is only about twelve and a half pounds, it’s a very small appliance it’s not going to be something that is going to be oversized for even a small room.
6.Extra replaceable filters or special up-gradable filters
For example medium filters or an example of an extra filter and pet filters are an example of a upgraded filter. Note that here we’re not talking about washable pre-filter.
Now just like anti microbial filters there’s nothing wrong with these extra filters or upgraded filters but at the same time our tests have shown that these extra filters Or the additional filters or special upgraded filters really don’t do much in terms of overall particle filtration and gas filtration.
Extra filters especially can keep the HEPA filter and/or the carbon filter from saturating as fast. But now you have to replace an additional filter, so the cost savings in terms of keeping those filters from saturating as fast meaning that you don’t have to replace them as often.
Those cost savings are offset by the fact that now you have an extra replaceable filter that you have to buy for the air purifier. Upgraded versions of filters are also not as great as they may seem. The upgraded filter very rarely does a better job than the regular filter and the fact is that those upgraded filters are much more expensive to replace.
So you are essentially purchasing the air purifier with an upgraded air filter that is doing very little in terms of improving particle filtration and at the same time that upgraded filter is going to cost more to replace each and every time you have to replace the unit’s air filters.
Now with all of that being said, let’s get into
What is actually important when you buy an air purifier?
Particle Filter Type
We strongly recommend a unit equipped with a HEPA filter, not a “HEPA Type” filter, not a “Permanent Filter”, not a “Proprietary Particle Filter”, but a true HEPA filter with an efficiency rating of 99.97%.
A HEPA filter will be able to remove nine thousand nine hundred and ninety seven of every ten thousand particles that travel through that filter. This is the “Gold Standard” air filter that you want equipped on the air purifier that you end up buying.
Then we look for Gas Filter Type
Now HEPA filters do one thing very well, they capture and trap solid particles but they cannot capture gases. A different filter is necessary to capture gases. The industry standard for this task of gas filtration is an “Activated Carbon Filter”
Now two types of carbon filters dominate the market. Number one is a thin replaceable filter that is made of a fibrous material and that fibrous material is coated with carbon.
Number two is a thicker washable filter, featuring a honeycomb design and inside of the plastic honeycomb frame of these filters, there are actually small carbon pellets, that is the second type of carbon filter
So, on the one hand you have a fibrous material coated with carbon and on the other hand you have a carbon filter that consists of pellets of actual carbon. We can discuss all the reason why we prefer pellet based carbon filters over fibrous carbon Filters, but for that, we need a whole new article to explain that, but suffice it to say here that pellet based carbon filters are generally better for gas filtration.
So, if you are concerned about filtering out gases such as odors or VOCs(Volatile Organic Compounds), the pellet based option is going to be the better option for you.
Earlier we talked about how you don’t need extra filters or upgraded filters when purchasing an air purifier however you do want to look out for a separate washable pre-filter.
The biggest benefit of a separate washable pre-filter is that it’s going to greatly extend the life of the HEPA filter and the carbon filter. If the pre-filter were not there, those other filters would saturate very quickly with larger particles and the pre-filter prevents that from happening.
The pre-filter is going to saturate with those larger particles and you are able to wash that filter and so you don’t have to worry about those larger particles saturating the carbon or the HEPA filter quickly.
CFM (Cubic Feet of air the air purifier processes each Minute)
HEPA filters are extremely efficient in filtering out particles. Again the efficiency there is 99.97% it’s almost a hundred percent efficient. It’s a very efficient filter. However for the HEPA filter to actually be able to filter out the particle, it needs to have access to the air that contains the particle and that access is granted by CFM or output.
Inside the air purifier, there’s a fan and depending on the size and the speed of that fan the unit will be able to process more or less air through its filters and so you want to look for an air purifier that has a higher CFM if possible.
Air purifiers don’t draw a particularly large amount of power. There are a few models on the market that do absolutely draw several hundred watts of power but most tend to draw 100 or less watts of power. So power draw is not the biggest concern but there are certainly air purifiers that are much more energy efficient than others.
Air purifier noise output does vary quite a bit and of course the biggest factor affecting that variance is the fan speed and that is something that you will set manually on the air purifier. So, depending on the specific model you will set the fan speed to low, medium, high. Maybe there’s a turbo setting but you will set that manually, so you will decide the actual noise output of the air purifier.
However, that is not to say that certain units do not provide a higher CFM of output compared to their noise output rating. And that is something that we look for in our individual product reviews. We look for units that have a high CFM per DB of noise output ratio and that gives us a good idea of the noise output efficiency if you will of the particular unit.
On this point of Value, the discussion can be broken down into initial cost and long-term cost.
For initial costs, you obviously consider the price of the actual unit, the price paid initially for it but you also definitely want to consider the output here. Certain units have a high output, certain units have a very low output. Output varies quite a lot and output doesn’t always correlate with price.
Meaning, you will have many units on the market that have a very high price but definitely do not have a high output. Similarly you will have units on the market that have a very low price but may actually have a high output. So look at the actual output of the unit because that is going to determine the size of the area that you can use the unit and definitely consider that CFM that actual output compared to the price when you consider the units initial value.
For a long-term cost, you definitely want to pay attention to energy efficiency. Again these units do not draw a lot of power however there are differences in terms of energy efficiency between different units on the market and so you want to consider a unit that is more energy efficient versus a unit that is less if you are concerned about long-term cost for power costs.
Finally you also want to consider filter replacement cost. Now there are two things to look out for here. When it comes to filter replacement cost, number one is you want to make sure that the air purifier that you buy, that the filters are available from multiple sources. There are often unique brands that only sell their own air filters on their own websites and in that case they set the price.
Of course they do still have to set the price relative to other units. They cannot be too exorbitantly priced but generally we do see units that have filters that are available from multiple retailers, those filters tend to cost less just because there is actual price competition between the different retailers.
In terms of pricing the air filters, now the second thing you want to consider when it comes to filter replacement cost is the actual size of the unit and the corresponding size of the filter. Smaller air purifiers have smaller HEPA filters. They have smaller carbon filters. They often have lower quality carbon filters and so those smaller units tend to have filters that cost less to replace.
The filters are less expensive however the smaller air filters, those are often lower quality carbon filters. So not only are you getting a lower quality filter but you are also getting a much smaller filter for a lower price. So definitely don’t be fooled by smaller air purifiers that have smaller HEPA filters.
Make apples-to-apples comparisons, look at the output of the units, look at the actual size of the HEPA filters and compare HEPA filters that are of similar size instead of comparing units that have larger HEPA filters with units that have smaller HEPA filters and giving the edge to the smaller units just because their HEPA filters are smaller and therefore less expensive.
And that about wraps things up for all the important things that you absolutely need to take into account when purchasing an air purifier. As we considered all these important factors ourselves things like energy, efficiency, noise output, a particle filter type, gas filter type and so on and so forth we noticed a particular trend.
We noticed something very interesting and that is that around the hundred and fifty to two hundred dollar price range you’re able to buy a very high output air purifier that comes equipped with all of these filters that has very good energy efficiency, very low noise output and is still at a very affordable price.
So here we’re talking about 250 CFM units in the $150 to $200 price range. These units have a proper particle filter. They come equipped with a HEPA filter, a true HEPA filter. These units have a very good output. 250 CFM is a very high output that’s going to be enough for rooms upwards of 300 square feet and there are very few units on the market that actually have greater output than 250 CFM.
Units in this price range and at the CFM tended to have a higher energy efficiency than smaller units that is definitely a trend that we noticed. And that is that the smaller units were much less energy efficient than the units in the 250 CFM range. So that is another positive for these units is that high energy efficiency.
These units also tended to be less noisy than most of their competitors. Again, for noise output we look at CFM 2 DB ratio and especially on lower fan speeds we still saw a substantial CFM a substantial output with very low noise output and that was something unique to these particular units in this price range and at the CFM level.
Finally we also notice that these units were a great value. There are more expensive units upwards of 3 4, 5, even 6, 7, 8 up to $1,000. Our residential air purifiers that are more expensive, however those units don’t really provide that much more. These units at the $150 to $200 range, give you everything you want in an air purifier and they do so at a very affordable price point.
We considered energy efficiency when evaluating value. We also considered filter replacement costs and units in this 150 to 200 dollar price range at around 250 CFM were a great value all the way around.
Now the to 250 CFM units that fall in this price range that we specifically recommend are the two units we have. First one on the left is the Winx 5500 – 2 and on the right is Coway Mighty air purifier.
Both of these units are exactly what we just described. 250 CFM units that are equipped with HEPA filters and carbon filters that have a washable pre-filter that are energy efficient. They have low noise output and a great value.
Both of these units check all those boxes and they do so at a very good price point and so these are the specific models that we would recommend as the best air purifiers currently on the market.
And finally we should mention that we are constantly testing new units at this time. We strongly feel that these particular models are the best options for you if you are looking for an air purifier. However we are constantly testing new units so if those new units become available and we do find that they are better than the units that we discussed today, we will update our guide and if you have subscribed to our e-mail membership, we will let you know when it happens.
Frequently Asked Questions
What is a HEPA air purifier?
HEPA was originally developed for space travel, but is now also used in air purifiers to filter pollution from the indoor air. HEPA literally means: High Efficiency Particulate Air. HEPA are air filters that retain between a minimum of 85% and a maximum of 99.9999995% of all dust (most penetrating particle size) of 0.1 micrometer (µm), depending on the specific filter type. A Global standard for HEPA filter is ISO 29463.
How does a Hepa air purifier work?
A HEPA air purifier contains a fan that sets the air in motion. On the one hand, this provides a suction effect (the air is attracted). On the other hand, the air that passes through the HEPA air purifier is blown back. The nice thing is that through the air that is set in motion, an air cleaning application can be added by placing a HEPA filter. As already mentioned above, the HEPA filter has a number of classifications. With this, it is known up to which particle size is removed.
Can a HEPA air purifier filter the corona virus?
Corona virus particles will always be surrounded by a cocoon of breathing fluid (aerosols). The total diameter of these aerosols including the virus particle depends on the air humidity, but cannot be smaller than the dimension of corona virus particles. These have a size of 0.12 µm. There is an aerosol liquid around this. Based on the filtering efficiency and the aerosol sizes that may contain the corona virus, it is concluded that a HEPA will trap this virus. This reduces the aerosol concentration that may contain the virus in a room during the operation of the system.
We hope that this will give the beginner buyers some idea about choosing the best air purifier.
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