Why do we need air purifier buyers guide? Pollutants such as smoke from tobacco, wood burning, and cooking; gases from cleaning products and building materials; dust mites; mold; and pet dander all contribute to an unhealthy indoor environment that have ill effects on human health. We furnished here the helpful Air purifier buyers guide.
Air purifier buyers guide – what to know
CADR (clean-air delivery rate) rating. This measures the cleaning speed of the purifier for removing smoke, dust, and and pollen. Look for a CADR of at least 300, above 350 is really great.
Size guidelines. For proper efficacy, you need a model designed to work in the room size. Choose a model that is designed for an area larger than the one you are outfitting it for if you want to operate it at a lower, quieter setting.
AHAM (Association of Home Appliance Manufacturers) Verified mark. AHAM’s standards are design to ensure the safety, efficiency and performance of many home care appliances, including air purifiers. The standards are designed to provide a common understanding between manufacturers and consumers to help make the purchasing process simpler. While voluntary, most reputable air purifiers have undergone this certification program, which often provides a CADR rating and size guidelines.
True HEPA. True HEPA filters are effective at removing ultra fine particles (think: dust, dander, pollen, mold and other common allergens in the home). The industry standard for such is that the unit must be able to remove at least 99.97% of particulates measuring 0.3 micron diameter in a lab setting. Remember, it is important to note that in real life settings, the actual efficacy of these devices would be far less as new pollutants are constantly emerging. Note that there is no industry standard for the terms “HEPA-like” or “HEPA-type,” and are mostly used as marketing ploys to get consumers to purchase the product.
Types of Air Purifiers
There are several technologies air purifiers employ for tackling indoor pollution. Some work better than others. Some can actually be bad for your health.
Activated carbon filters. Rather than catch particles like mechanical filters, sorbent filters use activated carbon that can adsorb some odor-causing molecules from the air. They may also tackle some gases, but they’re not particularly effective against formaldehyde, ammonia, or nitrogen oxide. Because they don’t combat particles, many air purifiers will include both an activated carbon filter and a pleated filter for catching particles. Activated carbon gets saturated faster than a pleated filter, though, and requires replacement more frequently—every three months as opposed to every six to 12 months for pleated filters. And be prepared: Activated carbon filters cost up to $50 each.
CR does not currently test for odor removal, but we did conduct a one-off test in 2008 with five air purifiers that came with odor-removing claims. For this test, we assessed how well these machines removed cooking odors. The results: Only two devices were able to do so because they used very large and thick carbon filters.
Mechanical filters. This is the type we test. Air purifiers with pleated filters use fans to force air through a dense web of fine fibers that traps particles. Filters with very fine mesh are HEPA filters—those certified to collect 99.97 percent of particles of a certain size (0.3 microns in diameter—smoke and paint pigments, for example). HEPA filters can remove larger particles, too, including dust, pollen, and some mold spores while they’re suspended in the air. (Note that some filters labeled “HEPA-type” or “HEPA-like” have not been certified to meet the requirements of a true HEPA filter but may still perform adequately in our tests.)
As for limitations, mechanical filters don’t help with gases or odors. And they can be expensive to maintain. Mechanical filters need replacing every six to 12 months; they can cost up to $200 per filter but typically max out at $80.
Ozone generators. These machines produce ozone, a molecule that can react with certain pollutants to alter their chemical composition. This can result in dangerous indoor air quality, and CR does not recommend them. Makers of ozone generators often claim that the devices emit safe levels of ozone, but in the past, our tests found that even at low settings, some ozone generators quickly exceeded the Food and Drug Administration’s limit of 0.05 parts per million for medical devices. Plus, studies reviewed by the EPA have shown that low levels of ozone—the chief ingredient of smog—don’t effectively destroy indoor pollutants. Studies also show that ozone has been linked to decreases in lung function and increased risks of throat irritation, coughing, chest pain, and lung tissue inflammation. Ozone might also worsen asthma, emphysema, and bronchitis, according to the EPA.
Ultraviolet germicidal irradiation (UVGI). Some manufacturers claim their air purifiers kill airborne viruses, bacteria, and fungal spores with UV lamps. But some bacteria and mold spores are resistant to UV radiation. To work, the UV light must be powerful enough and the exposure must last long enough—minutes to hours rather than the few seconds typical of most portable UVGI air purifiers—to be effective.
Electronic air purifiers. Electrostatic precipitators and ionizers charge particles in the air, so they stick to plates on the machine or to nearby surfaces by a magnetic-like attraction. CR doesn’t typically test them or recommend them because they can produce ozone.
Photocatalytic oxidation. PCO uses ultraviolet radiation and a photocatalyst, such as titanium dioxide, to produce hydroxyl radicals that oxidize gaseous pollutants. Depending on the pollutant, this reaction can sometimes generate harmful byproducts, such as ozone, formaldehyde, nitrogen dioxide, and carbon monoxide. CR does not currently test PCO technology. There have been few field investigations done on the effectiveness of PCO air purifiers, but one laboratory study conducted by researchers at Syracuse University in New York reported that the devices did not effectively remove any of the volatile organic compounds (VOCs) typically found in indoor air.
What Types of Pollutants Can Air Purifiers Remove?
As you just learned, air purifiers are powerful machines that are designed to combat a wide variety of airborne pollutants.
But, what exactly are those types of contaminants?
Below is a list of the most common pollutants that air purifiers target inside your home.
- Plant spores and fungi
- Dust and dust mites
- Pet dander and hair
- Mold spores
- Bacteria and viruses
- Tobacco and wood smoke, and its smell
- Household odors from cooking, pets and chemical cleaners
- Toxins from aerosol sprays and pesticides
- Volatile Organic Compounds (VOCs) found in paint, varnishes, cleaning supplies, new carpet and building materials
Air purifier buyers guide – ACH and CADR Ratings
When you’re looking to buy an air purifier you’ll sometimes come across two common ratings in the specifications list.
Not all air cleaners have these ratings, but some do, so it’s good for you to know what they mean and how to compare two products that include these values.
ACH Stands for “Air Changes Per Hour”
This is one of the least understood ratings on air purifiers and often gets overlooked by consumers. However, it’s actually one of the most telling features about how efficient an air cleaner operates.
The ACH rating tells you how many times the device can exchange the air within a room with clean, fresh air every hour.
Common ACH ratings you’ll see on a device include 4x, 5x, 6x, etc.
A 4x rating means that the dirty air around in a space is removed and recycled with clean air four times per hour.
The higher the number, the more efficient the machine is at purifying the air inside a room.
It’s important to understand that this rating is directly tied to the maximum square footage the air purifier can handle. We’ll explain this in more detail in the next section on how to properly size an air cleaner for a room. For now, just know that if a product has a 4x rating and specified to cover 300 sq. ft., this means that if you place the machine in a room that’s larger than this it won’t uphold the 4x exchange rate. It will be much less efficient and the air will not be as clean.
CADR Stands for “Clean Air Delivery Rate”
This rating was developed by the Association of Home Appliance Manufacturers (AHAM) as a way to help consumers know how well an air purifying device can clean the air within a particular size room.
The goal of the CADR rating is to give you an objective standard to compare the effectiveness of a device.
The Environmental Protection Agency (EPA) offers these guidelines for minimum CADR ratings by room size:
|Area (square feet)
|Minimum CADR (cubic feet per minute)
Some air purifiers have a single CADR number, while others have different CADR numbers for smoke and similarly small particles, dust, and pollen and similarly large particles.
This rating is especially important when you’re comparing two or more air purifiers against each other and trying to decide on which one to buy.
However, it’s important to point out that not all air cleaning devices include a CADR rating on their list of specifications. Only manufacturers that have the AHAM independently test and certify their machine will display the CADR rating.
The major reason you want to look for the CADR rating is that it gives you an honest assessment of how large of a room the air purifying device can handle.
Unfortunately, the air purifier market is not as regulated around the world as you might think and manufacturers could list a maximum square footage rating on their device that may or may not be 100% accurate.
The CADR rating ensures that if a product claims to purify a space up to 300 sq. ft., that it has been tested and verified to be true. It also tells you exactly how well the device can get rid of certain types of indoor contaminants.
The CADR rating measures three types of air pollution:
- Tobacco Smoke
The measurement for each category can range anywhere between the numbers 10-450 and is displayed as a set of three numbers. For example, a CADR rating may be 200/220/190 where 200 refers to dust, 220 to tobacco smoke and 190 to pollen.
The higher the number, the more effective the air cleaner is at removing that type of contaminant.
When you’re comparing two or more air cleaners that have a similar square footage rating and include the CADR rating, those three numbers will clue you into which product is actually the better purchase for eliminating specific contaminants.
Just like other home appliances, air purifiers require electrical energy to operate.
Since air purifying devices need to run continuously in order to keep the air clean and purified, you’ll want to consider the amount of energy a device uses before buying it.
Most air purifiers use between 5-200 watts of power. It’s best to find a device that carries the Energy Star rating, which ensures that it uses the least amount of energy possible and is the cheapest to operate.
Trusted brand – Air purifier buyers guide
A list of companies you can trust include:
- Air Doctor
- Alen Air
- Austin Air
- Hamilton Beach
- Rabbit Air
Any of the air purifiers produced by these manufacturers above will be a top-notch choice.
Also, any marketing claims these companies make for a product are most likely accurate too.
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