Is A HEPA Filter Really Necessary? Should you choose a HEPA filter over other alternatives?
At first glance there may seem to be added expense in your initial purchase. You may feel that replacement filters will expensive and cumbersome. With so many air cleaners promising to be “silent” or have “no messy, expensive filters” you might feel that HEPA filter air purifiers are a second rate option. Is the marketing of well-heeled consumer product companies really doing justice to this mainstay of air purification?
I feel that many people are being misled by the disinformation of irresponsible marketing campaigns. That is one of the reasons for building this site. Multiple chemical sensitivity, allergy and asthma are problems I am personally familiar with. So finding effective air purification systems has been a priority in my life for the last fourteen years.
Ultimately I came to the conclusion that a HEPA air filtration system is the best solution available. I believe that you too will benefit from a HEPA air cleaner.
To explain why let’s start with the most basic questions you should ask when deciding on an air purifier.
Questions you should ask of any air purifier
- What will the air cleaner remove from the air? What will it not?
- How efficient is the air purifier? How effective is the technology it uses to clean the air?
- What size of air cleaner will I need? How many air changes per hour will it provide in that size room?
- How easy is it to change or clean the filter? How often is this maintenance necessary? What our the cost and availability of the filters?
- How much noisey is the sysyem, can I run it when I am asleep.?
With these questions in mind, how effectively does HEPA air filtration give the results you’ll be most satisfied with?
Evaluating HEPA air filtration
What will a HEPA filter remove from your home air? What will it not?
HEPA filters can also capture irritant particles like tobacco smoke. Usually some form of prefilter is used to trap larger dust particles that would prematurely clog the higher efficiency HEPA filter placed after it.
HEPA filters will not remove chemicals and odors. This is why they are often combined with activated carbon filters.
Of course, all filtering systems likewise claim to remove such particles. They likewise need to be supplemented in some way to remove odors and chemicals. The real advantage of HEPA air filtration is seen in its overall effectiveness versus these other air cleaners.
What is the efficiency rating of HEPA? How effective is the technology versus other air cleaning systems?
Only HEPA air filtration meets a standard recognized by government and industry. To receive the HEPA designation it must remove 99.97% of all particles as small as 0.3 micron in size.
While other filter media remove some particles at that size their efficiency varies and is often no greater than 50%. Even much larger particles like pollen may not be fully removed. The problem with non-HEPA filters is you have no way of knowing how effective they are.
Ion generators do not remove particles at all. Their method is to fill the air with charged particles that tend to attract other particles. These stick together and presumably settle out of the air more quickly. Some charged particles will stick to the walls and furnishings. This has been called the “black wall effect”. The EPA has expressed concern that these uncollected charged particles may even deposit within the lungs of exposed persons.
Ionic air cleaners that use collector plates are called electrostatic precipitators. Their efficiency at particle collection tends to be no greater than 80%, much less than HEPA air filtration. Studies have shown that the collection efficiency can be reduced to as little as 20% in as few as three days due to particle loading of the collector plates.
Some people claim that ozone generators clean the air by destroying the contaminants. Scientific studies have shown this to clearly not be the case. Ozone can react with pollutants but the partial breakdown byproducts that result can be more numerous and more dangerous than the original pollutants. Ozone generators’ efficiency at removing contaminants is essentially zero.
If you really want the most effective air cleaning available then HEPA air filtration is your best choice.
Will the air purifier clean the air in a room as large as you need? How many air changes per hour will it provide in that size room?
HEPA air filtration is the most effective means to clean large volumes of air rapidly.
Of course, these air purifiers come in a wide variety of sizes allowing you to choose according to your needs. Some Allerair air cleaners reportedly cover areas as large as 1800 sq. ft. However, that is at a reduced number of air changes per hour. Even so, the total capacity of these fan forced air cleaners is always far greater than other systems.
In ionic air cleaners that use no fan the speed of ionized air being pulled through the unit is quite low. This means a very much-reduced ability to clean large volumes of air.
Where ionic air cleaners have an added fan the air speed has to be kept low also. This is because a fast moving air stream would not permit the charged particles to be deflected onto the collector plates. Again, you don’t get the ability to clean large volumes of air quickly.
How easy to change the filter? How often is this maintenance necessary? Cost and availability of the filters?
One of the greatest scams in the air purifier market among non-HEPA air cleaners is to sell a cheap air purifier and then bilk the customer later with pricey regular filter changes. Sometimes the filters are hard to come by, either the store selling the air cleaner doesn’t carry the filters or is chronically out of stock.
The actual cost of a replacement HEPA filter may seem high compared to a non-HEPA filter. However, consider that replacement may be once every two, five, even eight years in the case of the Allerair AirMedic. This means the annual cost to have clean air is low by comparison.
With ionic air cleaners you avoid the cost of replacement filters but cannot avoid the necessity of constant maintenance cleaning of the collection system. Many owners have complained at how difficult it is to properly clean closely spaced collector assemblies. A collector grid that isn’t cleaned regularly doesn’t clean the air and can develop a residue on the plates that will not come off. This permanently reduces its ability to clean.
HEPA air filters are very easy to change. Manufacturers have made certain tools are never required and most can be completely replaced in less than five minutes.
All things considered, HEPA air filtration is simple, easy, low maintenance and low in long term cost while offering the best air cleaning possible.
How much noise does the filtration system make? Is it quiet enough to run while you sleep?
HEPA air filtration tends to be the noisiest because of the fan forcing air through the system. However, high quality HEPA air purifier manufacturers recognize this and do their best to keep noise levels as low as possible. All offer low speed settings that are quiet enough to sleep without disturbance.
If you choose the right size air purifier it will be able to give sufficient air changes per hour at a lower speed setting. This keeps noise low and gives you additional cleaning capacity at a higher setting in the event it is needed, like after a cooking mishap.
Ionic air cleaners may have an edge in the “silence is golden” department, but this comes at the expense of performance.
I encourage you to put greater value on air cleaning performance and choose HEPA air filtration.
If you would like to consider air purifiers from companies that keep your needs in mind and offer truly effective and reliable air purification IQAir, Allerair, Austin Air and BlueAir are among the best.