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If you have allergies or asthma or wondering if an air purifier can prevent the spread of the COVID-19 virus, then you have probably considered the purchase of an air cleaner. And that is especially true now when so many people are stuck indoors 24/7 because of the coronavirus pandemic.
There are so many makes and models on the market, choosing one can be overwhelming.
Many people give up the search because it is just too confusing. Others purchase the wrong type or model and are unhappy with the results they see because they purchased the wrong thing.
How do you know what air cleaner is best for your needs? HEPA air cleaner costs seem to run from inexpensive to extremely expensive.
Here is some information we have learned over the years and we hope it will help you so that when it comes time to buy a HEPA air cleaner, you will make the right choice for you and your family.
What is a HEPA Air Cleaner?
To be labeled a true HEPA air filter or cleaner, the filter must arrest very fine particles. HEPA is an acronym that stands for High-Efficiency Particulate Air. It is a measurement that says that 99.97% of particles as small as 0.3 microns in size will be captured or “arrested” by the filter. To be true HEPA, it must meet these standards.
This standard was developed during research to develop the nuclear bomb. Scientists knew they had very small, very toxic particles with which to contend and needed a method of protection. Thus, the HEPA filter was born.
If a filter is marked HEPA type or HEPA like or Hospital Quality, then that does not make it true HEPA. When in doubt, be sure to ask if it is true HEPA.
Is HEPA Air Cleaner Effective Against Viruses?
The flu virus is spread when an infected person coughs, sneezes, talks or breathes, emitting virus-containing particles (COVID-19 also known as Coronavirus). Those particles may directly contact another person, coat surfaces touched by others or float through the air, where someone else can inhale them.
According to a study by NASA - Submicron and Nanoparticulate Matter Removal by HEPA - Rated Media Filters and Packed Beds of Granular Materials - HEPA filters do have the ability to filter out ultrafine particles <0.01 μm.
“Contaminants generated aboard crewed spacecraft by diverse sources consist of both gaseous chemical contaminants and particulate matter. Both HEPA media filters and packed beds of granular material, such as activated carbon, which are both commonly employed for cabin atmosphere purification purposes have efficacy for removing nanoparticulate contaminants from the cabin atmosphere.The phenomena associated with particulate matter removal by HEPA media filters and packed beds of granular material are reviewed relative to their efficacy for removing fine (<2.5 μm) and ultrafine (<0.01 μm) sized particu-late matter.”
In another study, the CDC - Guidance for Filtration and Air-Cleaning Systems to Protect Building Environments from Airborne Chemical, Biological, or Radiological Attacks - state biological agents and radioactive particulates are efficiently removed by HEPA filters.
“Chemical and biological aerosol dispersions (particulates) are frequently in the 1- to 10-µm range, and HEPA filters provide efficiencies greater than 99.9999% in that particle size range, assuming there is no leakage around the filter and no damage to the fragile pleated media.This high level of filtration efficiency provides protection against most aerosol threats.
Chemical aerosols removed by particulate filters include tear gases and low volatility nerve agents, such as VX;* however, a vapor component of these agents could still exist. Biological agents and radioactive particulates are efficiently removed by HEPA filters.”
What is the Difference Between a Filter and a Purifier?
A filter by definition removes particles from the air by trapping them and preventing them from becoming airborne again. A purifier removes particles or odors from the air. It may or may not use filtration to achieve purification.
For example, some air cleaners are not filters but ionizers. An ionizer causes particles to fall from the air or to stick to electrically charges rods or plates. An ionizer does not filter the air. An ionizer is not a HEPA air cleaner: it is an air purifier.
Some air cleaners utilize various forms of technology (such as Airfree TSS) to incinerate pollutants. These air cleaners will pull air into the unit, expose it to extremely high temperatures to burn off any particles, and then release air back into the room. These units are air purifiers and not HEPA air cleaners.
Some air purifiers emit a super-oxygenated substance called ozone. Ozone is oxygen that consists of three molecules of oxygen instead of the normal two molecules in the oxygen that we breathe. This third molecule acts as an oxidizer or free radical to remove pollutants from the air.
Ozone is very effective from removing organic odors but is toxic in large doses. Ozone should not be used in occupied areas and never around people with asthma or allergies as it is a respiratory irritant as well.
Unfortunately, some companies market ozone generators as air purifiers. These units are not HEPA air cleaners.
How Do I Pick the Best Air Cleaner?
The most important thing in making your air cleaner decision is the size of the room that you must clean. Large rooms need machines with large motors and large filters. Small rooms such as a dorm room or office cubicle can be cleaned with a smaller air cleaner with a small motor and a small filter.
When evaluating a HEPA air cleaner, you want to know about the motor. The filter can only trap the particles in the air if they ever make it to the filter. Moving the air requires a motor and a fan.
These are mechanical parts and they are going to make some noise. A good air cleaner minimizes this noise, but a “silent” air purifier isn’t moving air. Even if the motor and fan were silent (unlikely) you should still hear the air move. Even the wind makes noise when it blows. Your air cleaner is the same.
The faster an air purifier can cycle air through the filter, the faster it filters out the particles.
If you look at the specifications for the unit, you should see the power of the motor as expressed in the number of cubic feet per minute of air it can move. This may be referred to as the ‘CFM” of the motor. The higher the CFM, the better the filter can clean.
Some are cleaners show CADR (Clean Air Delivery Rate). CADR reflects, in cubic feet per minute, the volume of clean air that an air purifier produces at its highest speed setting. At lower speeds, the rate a machine is able to clean air decreases.
How To Determine What Size Air Cleaner I need?
To determine the right size machine for the room, you need a couple of bits of information.
First, you must know how much air is in the room. In case you forgot, the volume is calculated by multiplying:
Length of room x width of room x ceiling height
A 10 x 15 bedroom with standard 8-foot ceilings has 960 cubic feet (10x15=150 120 x 8 = 1,200). That’s important to know. If you only looked at the square footage, you’d think you just had to clean 150 feet. But that’s 8 times less than you really have.
Take a very close look at the machine you are thinking about buying. The technical specifications will tell you how much air the motor can move. It will be expressed as a number with the letters “cfm” behind it. That means the volume of air the machine can filter expressed in cubic feet of air per minute.
For example Austin Air HM400 Healthmate air cleaner: Speed (3) 400 CFM
To determine air exchanges, take the volume of air in the room and divide it by the cfm of the machine. That will tell you how long it will take to get one air exchange. Or, in other words, how long will it take for that machine to move all the air in the room through the filter once.
To determine the air exchanges per hour, divide 60 (the minutes in an hour) by the number of minutes for one complete exchange.
Using our Austin HM400., the air in our 10’ x 15’ bedroom will change 20 times per hour when the air cleaner running on high.
60 / (Cubic feet of room / CFM of the air cleaner)
You want at least 4 to 6 air changes per hour. 10 is great and more than 10 is even better!
Something else to consider is the size of the filter. Machines with small filters will need to have the filters replaced frequently. Not only filter changes a chore, but they add to the operating expense of the filter. You want a filter that is large enough to last several years unless you are willing to spend the time and money on frequent filter changes.
Stay away from machines with washable filters. These are generally pre-filters. If a “washable” filter is not thoroughly cleaned, rinsed, and dried before it is returned to the filter, it can harbor molds and bacteria. In that case, washing the filter just made the situation worse and not better.
Another consideration is if you want your HEPA air cleaner to remove anything else besides particles. Some makes of HEPA air cleaners utilize carbon to remove gasses and odors that ride on gasses.
AirPura makes a HEPA air cleaner that is specifically designed to remove tobacco odors and chemicals. In addition to HEPA filtration, the Airpura T600 has filtration for tar and the chemicals found in tobacco smoke.
A final consideration is a warranty. If there is a problem with the machine, what is the warranty and what does it cover?
A quality HEPA air cleaner will not be inexpensive but should last for many years. As with any appliance that has a long life, the warranty is important to understand any limitations before you make a purchase.
If you are not sure what air cleaner would be best for your room size and budget, give The Allergy Store a call at 1-800-771-2246.
Be sure to know the size of the room in which the air must be cleaned and what you hope to remove from the air before you give us a call. Based on your personal situation, we will be able to recommend the proper air cleaner for your needs.
Wishing you the best of health
The Allergy Store
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