Does a HEPA Air Purifier REALLY Work?
Before buying a HEPA air purifier, you may ask whether HEPA air purifiers work and whether they are effective and will make a difference in your life.
These are good questions to have. After all, HEPA air purifiers can be quite costly.
This article is going to examine the effectiveness of HEPA air purifiers and whether they are good investments for your needs. But, before looking at HEPA air purifier’s effectiveness, let’s talk briefly about what HEPA filter means and how it works.
- Does a HEPA Air Purifier REALLY Work?
- True HEPA vs HEPA-like Filters.
HEPA Air Filters at a Glance
HEPA air purifiers are a type of air purifiers which clean the air through the use of a HEPA filter. HEPA here stands for High Efficiency Particulate Air. This kind of filter is capable of filtering particles up to 0.3 micron in size at 99.97% efficiency. They also can filter particles smaller than 0.3 micron, such as gases and volatile organic compounds (VOCs), but at a reduced efficiency.
It is important to note that only a true HEPA filter will work in this capacity. Many other filters in the market, even the ones marketed as HEPA-like, do not have this capability. In fact, HEPA-like filters are found to have 99.97% efficiency in capturing particles 2 micron or above only, as opposed to true HEPA filters which are capable of filtering 0.3 micron particles. Other filters are even worse, as they’re only capable of catching mostly visible dust (10 micron or higher).
The Significance of 0.3 Micron.
You may think that sure HEPA filters can filter out particles even up to 0.3 micron at high efficiency. But so what ?
What is the significance of that 0.3 micron ?
You see,the air that we breathe consists a lot of particulates, sized from 0.0001 micron to 10,000 micron. Particles bigger than 5 micron, including visible dust (10 micron or above) and pollen are easily filtered by our nose. Anything smaller than 0.3 micron have a better chance to be exhaled by our lung.
Any particulates sized between 0.3-5 micron, which consist of small allergens such as mold, bacteria, animal dander, dustmite and fumes, easily get to our lung, but are not small enough to be exhaled easily by our lung. This is the size of particulates most efficiently trapped by a HEPA filter. Hence, an air purifier with HEPA filter is a good choice if you want to minimize the presence of lung-damaging particulates in your surrounding.
Do HEPA air purifiers work ?
If you ask whether a HEPA air purifier works, then the answer is yes. HEPA air purifiers really work if the HEPA filter is a true HEPA and you have a need to get rid of small and larger allergens. In other words, if you suffer from allergy, be it a mold, pet, pollen, or dust allergy, chances are a good quality HEPA air purifier will make a difference in your life.
In order to be really effective, a HEPA air purifier, should also have a tight housing, so that the machine does not leak dirty air. You can only get an air purifier with tight housing if you buy at least a second tier air purifier with good ratings. Certainly, you will get the best if you buy a premium kind.
(To see air purifier tier system and what air purifier gets what tier, go to our HEPA air purifier review page.)
Will HEPA air purifiers work for asthmatic and people with COPD, compromised immune system and chemical sensitivity?
As alluded above, HEPA air filter is most efficient for particles 0.3 micron and above. Most people with asthma or COPD, compromised immune system and chemical sensitivity need to get chemical fumes, volatile organic compounds, viruses, smoke, and additional germs controlled as well.
Unfortunately, they are mostly smaller than 0.3 micron and constitute more than 90% of air particulates. Most standard HEPA filters would not be able to trap most of these smaller particles efficiently, although there are a few premium air purifier’s manufacturers who produce their own proprietary enhanced HEPA filters which are effective to curb particles smaller than 0.3 micron.
But in general, if you need a strong gas, virus, smoke, and chemical controls, you would need to have a good quality HEPA air purifier with additional filter or mechanism to curb particles smaller than 0.3 micro.
Fortunately, most HEPA air purifiers from second tier and premium kind also include some kind of gas control filter.
For instance, if you really need a smoke control, then a purifier with a healthy amount (at least 2 lb) of activated carbon which will curb organic gases will do good. For most control though, you would need a ‘multi gas’ kind of machine which will curb additional chemical gases as well, such as IQAir Multi Gas, and so forth.
Only when you buy a HEPA air purifier with appropriate gas and germ control that HEPA air purifiers work for people with respiratory problems and chemical sensitivity.
Why Don’t Air Purifiers Seem Not to Work Sometimes?
Some people think that air purifiers are all marketing, and no substance. But, the fact remains that air purifiers, especially HEPA air purifiers work for people with health problems.
However, it is important that before investing in a costly machine to assess whether your expectations line up with what a particular HEPA air purifier is capable of doing, and their safety.
For instance, if you have a dust and cold weather-induced asthma, you can only expect some, but not complete relief, upon getting a HEPA air purifier. Because of course, no HEPA air purifiers can help to lower your surrounding temperature. On a similar note, if you know that you need a proper gas control because of your asthma, then make sure to get a good quality HEPA air purifier with gas absorber.
In this condition, it is not appropriate to buy a cheap air purifier with a HEPA-like filter with non-tight housing and no gas absorber. This kind of air purifier is only designed to curb mostly visible dust and is only good for all around cleaning. So, it will not help you at all.
Finally, it is important to remove the source of contamination in your home. For instance, if you are allergic to a certain pet and still keep pets at home, then it can be expected that air purifier can only alleviate, but not completely remove, the symptoms.
(For more discussion on this, look at our article on whether air purifiers really work)
All in all, HEPA air purifiers work to alleviate symptoms dramatically. But, in order for it to be effective, you have to be prepared to select the the most appropriate indoor air purifiers for your needs , know how to choose good quality HEPA filter air purifiers and, if possible, remove the source of contamination.
True HEPA vs HEPA-like Filters.
If you’ve been researching to buy a HEPA air purifier, you may have noticed that some HEPA air purifiers have true HEPA filter, whereas others have HEPA-like filter.
What do these mean and what is the difference ?
HEPA filter is a type of filter which is capable of filtering air particulates sized 0.3 micron or above at high efficiency (99.97%). This means, that when a True HEPA filter is used in an air purifier, then theoretically it should be able to capture big and small allergens sized 0.3 micron or above, including dust particles, dust mites, pet dander, mold, pollen, fumes, and some bacteria, with high efficiency.
This also means that a true HEPA air purifier with a good construction which allows no or only little air bypassing the filter should have an efficiency close to the theoretical efficiency value of a true HEPA filter. It is also common that such high quality true HEPA air purifier is also equipped with additional filtering mechanism to capture the smallest air particles, including gases and viruses. This kind of air purifier, would be highly suitable for people who have real problems to address.
In contrast, HEPA-like filter is not a true HEPA filter. It is a filter that is capable of filtering air particulates most efficiently when these particles are sized around 2 micron or above. Therefore, while this kind of filter is good enough to capture all visible dust (note: visible dust has a size of 5 micron or more) and other bigger allergen, like pollen and some of pet dander, it is not good enough for people who are more sensitive to air contaminants.
This is because of the filter’s limited capability in capturing smaller allergens. If you have a very mild allergy and is planning to use your air purifier to help you with all around cleaning, then HEPA air cleaners with HEPA-like filters are suitable for you.