Air Purifiers FAQ

Why do I need an air purifier?
An air purifier will improve your health. Americans spend about 90% of their lives indoors. The Environmental Protection Agency (EPA) estimates that, on average, indoor air is two to five times more polluted than outdoor air. AchooAllergy has a wide variety of air purifiers including Austin Air, Blueair, AllerAir, and IQAir.

What causes indoor air pollution?
Modern homes are sealed tightly for energy efficiency. Energy efficient homes are good for your electric bill, but bad for your allergies. Those tight seals trap all kinds of contaminants in your home: pollen that blows in when a door or window is opened, cat dander that hitches a ride on clothing, or chemicals and irritants released by cleaners and perfumes. Pollutants like tobacco smoke, pollen, mold, dust, and animal dander can cause asthmatic and allergic reactions, making homes unpleasant and unhealthy for allergy and asthma sufferers. Other contaminants, like chemically reactive gases and volatile organic compounds, can cause allergic reactions and more serious health problems.

Even if your symptoms are not noticeable now, that doesn't mean the air inside your home is clean. According to the EPA, health affects may show up only after long or repeated exposure; therefore, it's a good idea to clean the air in your home now, especially if you have kids. Prolonged exposure to airborne allergens and pollutants can cause allergies (and more serious health problems) to develop later in life.

What is a HEPA filter?
HEPA stands for High Efficiency Particulate Air. HEPA air purifiers were originally developed by the Atomic Energy Commission to capture radioactive dust particles. Our HEPA air purifiers will not filter radioactive particles, but they will take care of common allergens like pollen, mold spores, dust, etc. By definition, a HEPA filter removes at least 99.97% of all particles as small as 0.3 microns.

How do HEPA air purifiers work?
The inlet grill draws in dirty air. In most HEPA air purifiers, a washable pre-filter traps larger particles. By definition, a HEPA filter removes at least 99.97% of all particles as small as 0.3 microns. HEPA air purifiers were originally developed by the Atomic Energy Commission to capture radioactive dust particles. Allergens such as pollen, animal dander, mold spores, and dust get trapped in the filter. Many HEPA air purifiers also contain a carbon filter to capture chemicals, odors, and gases. Once the dirty air is purified, a fan sends it back into the room as clean air.

What is a micron?
Air purifiers are designed to eliminate impurities in the aireven those impurities which are so microscopic that they are invisible to the naked eye. Microns are used to measure the size of these microscopic airborne particles. Microns are used to measure airborne particle sizes. One micron is 1/25,000 of an inch. To give you an idea of how small this is, dust mites average around 300 microns, and a grain of sand can be over 800 microns!

What is a micron?

What is a HEGA filter?
HEGA stands for High Efficiency Gas Absorption. A HEGA cloth is an advanced military carbon cloth that is specifically designed for the filtration of areas polluted by smoke, odors, gases, smog, and fumes. These types of filters are specific to certain Austin Air models, such as the Austin Air Allergy Machine and the Austin Air Baby's Breath air purifier.

What is a HyperHEPA filter?
The IQAir Air Purifiers use a HyperHEPA filter which has more capacity and a longer life than a conventional HEPA filter. The HyperHEPA filter extends air filtration down to .003 microns. This is 100 times more effective than a standard HEPA filter.

What is an activated carbon filter?
Activated carbon and charcoal filters excel at adsorbing odors and gases and neutralizing smoke, chemicals, and fumes. "Adsorb" is not a typo; "adsorption" occurs when materials attach through chemical attraction. Activated carbon has been treated with oxygen, opening up millions of pores in the carbon. There are so many of these tiny pores that one pound of activated carbon has a surface area of 60 to 150 acres! This huge surface area makes it ideal for adsorbing gases and odors. These chemicals and gases are too small to be trapped by a HEPA filter, but they bond to the enormous surface area in the activated carbon. The bigger the carbon filter, the more chemicals it will be able to adsorb and the longer it will keep on working. When it's full, it can't adsorb any more and has to be replaced.

What is an impregnated carbon filter?
Impregnated carbon filters contain an additional chemical (a "chemisorbent") to eliminate certain chemicals like VOCs.

What is CADR?
CADR stands for Clean Air Delivery Rate, and it is a measurement developed by AHAM, the Association of Home Appliance Manufacturers. The CADR measures how much clean air an air purifier delivers to a room in cubic feet per minute (CFM).

What is ACH?
ACH stands for Air Changes per Hour. This number, also known as the ACH rating, tells us how frequently the air purifier can exchange all the air in a given room. For example, if the purifier has a ACH rating of 6 for a 20' x 20' room, then it is capable of exchanging all of the air in that room 6 times every hour. If you have allergies or asthma, you want an ACH rating of at least 4 and preferably 6 or 8.

Why doesn't sell ozone generators or ionic air cleaners?
Ozone generators produce the gas ozone, and ionic air cleaners also produce ozone as a by-product. Ozone is a molecule composed of three oxygen atoms; its the same molecule that makes up the "ozone layer" of our upper atmosphere. Stratospheric ozone is a good thing because it protects us from dangerous UV rays; however, ozone in the air we breathe can be harmful to your health. The U.S. Environmental Protection Agency (EPA) states that "relatively low amounts can cause chest pain, coughing, shortness of breath, and throat irritation. Ozone may also worsen chronic respiratory diseases such as asthma and compromise the ability of the body to fight respiratory infections."

The EPA warning continues: "Available scientific evidence shows that, at concentrations that do not exceed public health standards, ozone is generally ineffective in controlling indoor air pollution."

The EPA advises the public to "use proven methods of controlling indoor air pollution," which include eliminating or controlling sources of pollution, increasing outdoor air ventilation, and using proven methods of air cleaning, such as HEPA air purifiers.

Additionally, the American Lung Association (ALA) agrees that "ozone is a potent lung irritant and exposure to elevated levels is a contributor to the exacerbation of lung disease; it is especially dangerous for persons with asthma and other chronic lung diseases, children, and the elderly."

The ALA recommends against the use of ozone generators because "ozone generators, negative ion generators, and certain other electronic air cleaners that are not listed by the FDA, or cannot otherwise prove that their ozone emission levels are lower than 0.05 ppm, may produce levels of ozone recognized as unsafe for humans and are not recommended for use in occupied spaces because of the risk of generation of ozone." The ALA also reports that exposure to elevated ozone levels can cause some children to become asthmatic.

Consumer Reports, the National Institute of Occupational Safety and Health (NIOSH), and the U.S. EPA concluded that tabletop and room unit ozone generators are not effective at improving indoor air quality.

Many of our competitors sell ozone generators and ionic air cleaners, but we want to help you breathe better with products that are scientifically proven to work safely and effectivelyand we would never sell a product that may be harmful to your health. That is not a chance we're willing to take.

What are electrostatic filters, or electrostatic precipitators?
Electrostatic filters use an electrostatic charge to attract pollutants and trap them on collector plates. Electrostatic precipitators use electronic cells to charge particles within the purifier and immediately trap the impurities on collector plates. The main advantage with this type of air purifier is that the collector plates never have to be replaced; they can be easily washed in the dishwasher. But if the collection plates are not cleaned frequently, they quickly lose efficiency. Be aware that some electrostatic precipitators also generate ozone, which is a known lung irritant.

What are charged media filters?
Charged media filters work the same way as electrostatic precipitators, but they collect particles on traditional fiber filters instead of plates. The advantage of these filters is that they are able to collect very small particles, sometimes as small as 0.1 microns, through a combination of a filter and an electrostatic charge. The disadvantage is that, like the electrostatic precipitator filters, charged media filters lose their efficiency fairly quickly, and they can require more frequent filter replacements compared to HEPA air purifiers. These types of units can emit ozone, but the better ones on the market do not. If you are planning to purchase this type of air purifier, make sure that it does not emit ozone. The best air purifier in this category is the ultra-quiet Blueair air purifier.

How loud are air purifiers?
Some air purifiers, such as the Blueair units, are extremely quiet, while others can be quite loud when operating at high power. If possible, ask for a demonstration before you buy your air purifier. Also, please see our Air Purifier Noise Graph.
How loud are air purifiers? Air Purifiers Noise Level Graph
Air Purifiers Noise Level Graph

How often do I need to replace the filter(s)?
If you are buying a HEPA air purifier, don't forget to check and see how much replacement filters will cost. If your unit includes both a HEPA filter and a carbon filter, or other combinations of filtration media, they will probably need to be replaced separately, and they may last for different periods of time.

How do I know when to replace the filter(s)?
Luckily, you can take the hassle out of filter replacements by joining the
Clean Air Club, our free filter replacement reminder program. Well do all the work for you and automatically remind you when its time to replace your filter(s).
Air Purifier Clean Air Club
Air Purifier Clean Air Club - a free filter replacement reminder program

Should I run my air purifier all the time?
We recommend that you run your air purifier continuously for optimum operation.

Will the air purifier clean the air for my whole house?
No, a single air purifier will not clean the air in your entire house. Even whole house systems will not effectively clean the air in your entire house. You should examine your homes indoor air quality on a room-by-room basis. The bedroom is the most important room in terms of air quality, since you spend about a third of your life there. If you spend a great deal of time watching TV, you may need an air purifier for your TV room. If you dont spend much time in certain rooms, you probably dont need an air purifier in them, but youll still want to make sure your whole house is well-ventilated. Its also a good idea to periodically open windows and let in fresh air (if youre not allergic to pollen).

Where should I put my air purifier?
If you suffer from allergies (especially if youre allergic to dust), then the best place for an air purifier is your bedroom. Its essential to have clean air in your bedroom because you spend about a third of your life there. If youre allergic to animal dander and have pets, then you may want to place an air purifier in the room where your pets spend most of their timeand keep the pets out of your bedroom! Also, you should not place an air purifier in the corner of a room; it should be at least a couple of feet away from the walls for maximum air flow.

Am I going to see a significant difference on my electric bill?
Like all appliances, different air purifiers use different amounts of energy for operation. Unlike most appliances, air purifiers run continuously, so you may want to consider your utility bill before buying an air purifier. (If only volts and amps are listed, simply multiply the two: volts x amps = watts.) Typical HEPA air purifiers can use anywhere from 50 watts on low to 200 watts on high. For comparison sake, a typical lamp uses about 60 watts, while a typical computer uses about 365 watts. Therefore, while its wise to consider energy usage, most air purifiers will not create a significant difference on your electric bill.

How much does it cost to operate an air purifier?
Besides the electric bill (see above), you should also consider the cost of filter replacements. Its important to replace filters on time in order to keep your air purifier working properly. Some air purifiers dont require any replacement filters. Others may have multiple filters (pre-filter, HEPA filter, and carbon filter) that need to be replaced at different times. For a typical HEPA air purifier, the HEPA filter should be replaced every three to five years, and it costs between $70 and $200; the pre-filter should be replaced every three months, and it costs between $20 and $30; and the carbon filter should be replaced every six months, and it costs between $15 and $100. Please note that the previous prices and times are only examples.

Different air purifiers have different recommended times for filter changes, and the cost of replacement filters varies with different air purifiers. Please see our Air Purifier Replacement Filter page if youd like to further examine the costs of replacement filters. And if youre concerned that you might forget to change filters on time, please join the Clean Air Club, our free filter replacement reminder program. When you join the Clean Air Club, well do all the work for you and automatically notify you when its time for a filter change. Members of the Clean Air Club receive emails with special web links to make sure they order the right filters.

Whats the best air purifier for someone with asthma?
We recommend HEPA air purifiers for our customers who suffer from asthma. If you or someone you love has asthma, avoid ozone generators and ionic air cleaners.

What are the differences in your air purifiers?
We offer a wide variety of air purifiers designed to treat a number of indoor air quality problems. There are many factors to consider when shopping for an air purifier, but the main factors to consider are the type of pollution which youre trying to eliminate and the size of the room the air purifier will be used in. See our Air Purifier Buying Guide for more information about what you should consider before buying and air purifier. Also you can check out our compare air purifiers page and our Top 10 Air Purifiers list for a more in-depth look at the differences in our air purifiers.

What else can I do to clean the air in my house?
You should make every possible effort to remove the pollutant at its source. If you think you might be allergic to mold, make sure you don't have a mold colony growing in your basement. (If you do have mold problems, you need a dehumidifier.) If the offending irritant stems from chemicals or gases, then bringing in fresh air can result in a huge improvement. Also, some activities create high levels of pollutantslike painting, sanding, or cleaning with harsh cleaners. If possible, it's a good idea to open up the house and ventilate as much as possible when participating in these sorts of activities.

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