What are HEPA air purifiers ?
These are air purification products which clean the air by using HEPA filters or High Efficiency Particulate Air filters. These filters in general, are high-efficiency filters capable of filtering particles up to 0.3 microns in size at 99.97% efficiency. This includes large allergens like pollen and visible dust as well as smaller allergens in the range of 0.3-5 micron, such as pet dander, dust mite, mold spores, some bacteria, smaller dust, and fumes.
In addition, they also can filter particles smaller than 0.3 microns, such as some smokes, tiny germs, and so forth, but at reduced efficiency.
How Do these HEPA Air Purifiers Work ?
Basically, purifiers clean the air by passing the dirty air through the HEPA filter and exhaling the clean air out to the room. Some HEPA purifiers are equipped with a pre-filter so that the big particulates in the dirty air hit the cheaper filter first and leave the HEPA filter to deal with finer particulates. That way, this expensive filter does not have to be replaced so frequently.
Although these filters eliminate particulates which are 0.3 microns or bigger, the majority of particulates (90%) including gases are smaller than that. Sure the smaller particulates (smaller than 0.3 micron)are easier to exhale from the lung, but for people with health problems or with overwhelming number of such fine particulates in the surrounding (for instance: smoke, chemical out-gas, pet odor), it helps to have a HEPA air purifier which is equipped with a gas absorbent, such as a chemical or carbon filter. Hence air purifier manufacturers often also include a carbon filter, consisting of activated carbon, to help trap such fine particles. Of course, the ability of an air purifier to control odor and smoke also depends on the amount of activated carbon embedded in the unit. Some cheaper air purifiers usually have stripes of carbon, whereas premium air purifiers pride themselves for putting in 5 lb of carbon or more in the unit.
Finally, it is also known that HEPA purifier’s manufacturers sometimes include UV or other germicidal agents such as a silver screen in their units to help kill germs. Actually, a UV or germicidal agent is not a priority if the other filters do a good job in filtering small particulates. In this kind of unit, germs will automatically be filtered. In fact, most premium air purifier lines do not have a UV light or other germicidal agent. And yet, they are very effective in curbing dead particulates and live germs alike. The concern of having a UV light is that it can make the unit to produce ozone, a potential lung irritant, as a by-product.
In short, the stage of cleaning air using a HEPA purifier is as follows:
- Dirty air from surrounding is sucked up to the air purifier unit and is passed through a series of filters by the use of fan.
- Stage I (optional): The dirty air is passed through a pre-filter. Not all HEPA air purifier units have a pre-filter, but most have it to reduce the frequency of HEPA filter replacement.
- Stage II (optional): Some HEPA cleaners use carbon filter to filter out gases. So once the air is passed from prefilter, it gets to the carbon filter.
- Stage III: Air is then passed through the HEPA filter.
- Stage IV (optional): Air is exposed to the UV light to help kill microorganism.
Also Read: Top 15 Air Purifiers using HEPA Filter
Are these Purifiers Safe To Use?
In contrast to some electronic air purifiers such as ionizers and ozone air purifiers, HEPA filter purifiers are the safest air purifiers you can get. Since it works by mechanical means, there is no ozone, a potential lung and respiratory pathway-irritant, emitted. If you choose the ones with metal casing and non-toxic paint, there will be no out-gassing either.
Advantage of Choosing Air Cleaners With HEPA filter
- It works and has a high efficiency in curbing out lung-penetrating air particles.
- If you get a premium quality True-HEPA filter air purifier, there is a big chance that it will help your health problem.
Possible Drawbacks in Owning an Air Purifier with HEPA filter
- Maintenance cost can be expensive because of the need to replace the filter periodically.
- Possible hassle of installing the HEPA filter. You may need tools for changing this filter, but there are some air purifiers which are very easy to change. If you are DIY-challenged, make sure you get the one which has an easy-to-replace HEPA filter.
- Noisy. A HEPA filter air purifier needs a fan to draw air into the unit and to the filter. The higher the speed, the noisier it gets.
Is a Purifier using HEPA filter really worth it ?
So, is air purifier with HEPA filter worth it, considering the high cost of HEPA filter replacement, especially those that came from the top purifiers ?
To answer that question, and whether you really need the high-end HEPA air purifiers, you have to consider what your needs are. For instance, if you want to buy a HEPA-type air purifier for addressing a health problem, then you should know how severe the problem is, and what exactly the trigger for your health problem is. Only then you can get a HEPA air purifier which matches your needs.