What the Big Boys Don't Want You to Know About their Home Air Purifier Filters

Don't Dare Buy A Purifier Until You Learn the Secrets of Home Air Purifier Filters

Beware Home Air Purifier Trickery!

The home air purifier filters many manufacturers incorporate into popular HEPA air purifiers are not as effective as they may claim. Don't fall victim to their HEPA air filter hype. Read on to discover the many secrets about HEPA air filters and home air purifiers they can't afford for you to know.

This is the closely guarded inside information about home air purifier filters you need in order to find the Absolute Best Air Purifier.

The desire for manufacturers to tap their piece of the huge room air purifier market creates a clear conflict between your best interests and theirs. Millions of home air purifiers are sold in the United States every year, and have become standard appliances in many households and offices. Manufacturers of room air purifiers must strive - harder than anyone else in the air purification industry - to provide low cost products to their consumers. This has resulted in it being common to find room air purifiers with so called HEPA home air purifier filters technology selling for as little as $80.00.

While making an affordable home air purifier available to the masses is a commendable goal; misleading marketing statements and questionable air cleaner performance have many users disappointed.

Manufacturers of home air purifier filters and HEPA air purifiers use deceptive marketing tactics which are detrimental to your health and the credibility of the air cleaner industry as a whole.

Since the science of air cleaning is a complex one, finding one's way through the maze of unsubstantiated claims and misinformation is a difficult task even for the most alert and critical consumer.

Seven common industry practices in particular continue to confuse consumers and air cleaner professionals.

1. Theoretical Efficiency of HEPA Air Filters vs. Actual HEPA Filter System Efficiency

Due to the high efficiency, reliability and proven track-record, air purifier HEPA filter technology has become the industry standard for particulate filtration in critical environments, such as semi-conductor cleanrooms and hospital operating rooms. Recognizing the great marketing potential of the term "HEPA", many manufacturers are using it to project a high-performance image onto their room air purifier. What most HEPA filer air cleaner manufacturers conveniently omit to tell the consumer, is that their home air purifiers provide nowhere near the performance level of a commercial air purifier with HEPA air filter systems used in hospitals and cleanrooms.

Often consumers are misled about an air purifier's efficiency in removing pollutants. Statements like "effectively removes 99% of all airborne allergens" or "efficiently scrubs the room free of indoor air pollutants", lead consumers to believe that these home air purifiers remove virtually all of the impurities from the air in a normal indoor environment.

A Claim about HEPA home air purifier filters will often state 99.97% filtration efficiency. In most cases, this is also not true. The actual efficiency, for particles of 0.3 microns or larger, of many HEPA air filters sold today is below 80%. The "99.97%" refers to, in most cases, the theoretical efficiency rating of the filter paper that is used in the air cleaning device at 0.3 microns or larger.

The performance gap between a HEPA home air purifier and a HEPA-based commercial air purifier is mainly due to cutting corners in mass-production and profit maximization. There are a number of reasons why most HEPA home air purifier filters do not achieve actual performance levels that should result with true hepa air filter systems:

a). HEPA air filter media is not used.

b). The HEPA air filter media gets damaged during the pleating process (HEPA air filter media breaks easily).

c). There is leakage between the pleated HEPA air filter pack and the hepa filter frame.

d). There is leakage between the HEPA filter frame and the home air purifier filters housing.

Only very few manufacturers state the actual overall efficiency of their home air purifier filters, and even fewer guarantee and certify their room air purifier.

2. Overstating Actual Air Delivery Rates

Even the most efficient room air purifier in the world would not impact a room's air quality level, if it were not able to pass enough air through the home air purifier filters. The amount of air that a home air purifier is able to process (air flow rate) is usually expressed in cubic feet per minute (cfm). Consumers are often misled by exaggerated or false claims by manufacturers regarding air flow rates.

One common trade practice is to state the free-flow air handling capacity of the fan motor (i.e. without home air purifier filters installed), rather than the actual air flow rate (i.e. with all home air purifier filters installed).

Many manufacturers don't even make this vital home air purifier statistic available to consumers. Instead, many state a suitable room size, without mentioning how many air changes per hour the room air purifier would manage to produce in that size room.

Only very few manufacturers state the actual airflow rate of their device (with all home air purifier filters installed), and even fewer guarantee and certify their room air purifier's air flow rate.

3. ULPA is NOT Better than HEPA

In an effort to differentiate air purifiers from the mass of HEPA air purifiers on the market, some manufacturers have introduced home air purifiers which supposedly use ULPA technology. ULPA stands for Ultra Low Penetration Air and is used in modern cleanrooms. The difference between HEPA and ULPA is the efficiency rating of the media inside the home air purifier filter.

Typical HEPA air filter media has an efficiency of 99.97% at 0.3 microns, whereas ULPA media has an efficiency rating in excess of 99.999% at 0.12 microns.

Stressing the higher efficiency at smaller particle size, manufacturers of ULPA-based room air purifiers claim that these devices are superior to HEPA room air purifiers. Unfortunately, this is a perfect example where the search for a better sales pitch has resulted in an inferior product, since the reverse tends to be the case. All things being equal, a home air purifier that uses ULPA filter media will be less effective in reducing the particle concentration in a typical room, than the same air purifier equipped with HEPA air filter media. And as with many HEPA air purifiers, many ULPA-based air purifiers come nowhere close to actually delivering 99.999% particle-free air.

While ULPA filter media has the potential to remove more particles than HEPA filter media, that advantage is lost in room air purifiers, due to the reduction of air flow caused by the denser ULPA filter media. ULPA filter media typically allow 20-50% less air to pass than HEPA air filter media, resulting in fewer air changes per hour in a given room.

4. Ineffective Gas Phase Filtration

In many cases room air purifiers are purchased to deal with gaseous contaminants and odors. So it comes as no surprise that most manufacturers claim to use some technology to reduce gases and odors. Unfortunately, one of these purifier technologies in particular is designed to intentionally produce a toxic gas which is claimed to be an effective air cleaning agent. Manufacturers market these dangerous devices as Ozone Air Cleaners. THESE SO-CALLED OZONE AIR PURIFIERS ARE TO BE AVOIDED!

The most common technology adopted by manufacturers of home air purifier filters for the removal of gaseous pollutants is activated carbon.

While activated carbon in its granular form is unquestionably effective for the removal of many gaseous contaminants, most home air purifier filters on the market today use carbon fiber pads, which are only impregnated with activated carbon dust. These home air purifier filter pads contain only a few ounces of actual activated carbon and as a result, are essentially ineffective for the removal of gases and odors.

Some manufacturers claim that their activated carbon filter eliminates all gaseous pollutants and odors, a feat that is scientifically impossible. Specific gaseous contaminants need specific gas phase filtration technology. Activated carbon does not efficiently adsorb low molecular weight gases. For this reason, special sorbents are needed to effectively deal with pollutants, such as formaldehyde, hydrogen sulfide and ammonia.

Many room air purifiers that use granular activated carbon also use zeolite. Zeolite is a natural mineral, whose pore structure is supposed to be better suited for the removal for gaseous indoor air pollutants like formaldehyde and ammonia. In fact, there is no reliable scientific evidence to show that zeolite is able to remove any gaseous compound better than specialty impregnated carbons or impregnated alumina.

So why is Zeolite used? Zeolite is an inexpensive "filler" that is less expensive than activated carbon. Secondly, the concept of using two different substances to control gases and odors sounds quite promising to the unsuspecting home air purifier customer.

5. Sacrificing Long-Term Performance

While most tests and evaluations of air purifiers assess only room air purifier performance during its first few hours of usage, the real test for air cleaning effectiveness is long term performance. Unfortunately, most manufacturers cut costs on features that would enhance long-term performance.

One standard industry practice is the use of ineffective pre-filtration. In a HEPA air purifier, it causes the HEPA air filter to become clogged at a rapid rate. This in turn reduces the air flow rate, thus resulting in fewer air changes per hour in a given room. This is a particularly serious issue, since some home air purifier manufacturers inform consumers that their home air purifier filters will only need replacing every 3 to 5 years.

Insufficient pre-filtration, also, causes home air purifiers with substantial granular activated carbon filters to quickly lose their gas phase adsorption potential. Dust particles - that should be trapped by pre-filtration - clog the miniscule pores of the activated carbon filter media, and destroy its holding capacity to adsorb gases.

Another reason for poor long term performance of room air purifiers is that some air cleaning technologies suffer drastic reductions in air cleaning efficiency without regular maintenance or frequent filter change.

An electrostatic air purifier that uses charge precipitator technology will experience drastic efficiency reductions as the collector plates become covered with particles. One well known example is the Imfamous Ionic Breeze who's ionic air purifier collector plates must be regularly cleaned.

Some filterless ionic air purifiers have been known to produce increased arching and popping noises as the collector plates become saturated with particulates. A filterless air purifier in this condition could represent a fire hazard.

An electronic air filter that uses electrostatically charged fibers (electrete) also rapidly loose filter efficiency with particulate loading, especially in the presence of tobacco smoke.

6. Frequent and Expensive Replacement of Home Air Purifier Filters

While the initial purchase cost for many room air purifiers is relatively low, the cost of replacement home air purifier filters can be substantial.

Here are some reasons why many home air purifier filters often require frequent and expensive filter replacement:

· Lack of an effective pre-filters that protects the activated carbon and air purifier HEPA filter from premature clogging.

· Use of small filter cartridges with low holding capacity for pollutants.

· Filter replacement instructions that base replacement intervals of home air purifier filters on time passed (e.g. every 6 months) rather than actual usage and degree of air pollution.

· Combining several different home air purifier filter stages in one filter cartridge, thus forcing the user to replace all home air purifier filters at once, even if only one filter stage is used up.

7. Trying to be All Things to All People

While many home air purifier manufacturers offer several models, these models often vary only in size, rather than air cleaning technology. And since manufacturers like to have their product appeal to as many potential customers as possible, they sell one and the same home air purifier as the ideal solution for pet allergens, pollen, mold spores, microorganisms, tobacco smoke, odors, traffic fumes and chemicals, etc. In fact, some manufacturers claim that by virtue of using a multitude of air filter stages their room air purifier is more effective.

Unfortunately, the effectiveness of the room air purifier suffers, because more home air purifier filter stages mean higher air resistance and lower air delivery. Home air purifier filters that only contain filter stages matched to the user's requirements, offer superior filtration efficiency and air flow.


Comparison shopping for home air purifiers is not a simple task. Many variables must be considered including actual particle retention, gas phase filtration, and long-term performance of the home air purifiers.

So what are the lessons when evaluating home air purifiers?

Don't believe every claim made by manufacturers! Realize that for $80 you may be getting a seemingly affordable home air purifier, but you definately won't be getting the best air purifier on the market. As the old saying goes, you get what you pay for, and that's never been more true than in regards to a room air purifier with HEPA home air purifier filters. It's pretty much a rule that the low dollar home air purifiers will often have serious performance limitations.

Ask manufacturers to substantiate their claims with independent evidence. Check the underlying technology and investigate whether it has been properly implemented.

Of course, we've already done the research for you here.

All of the home air purifiers reviewed on this site were evaluated using tools that allow for an objective air purifier comparison, such as laser particle counters, to check manufacturer's particulate efficiency claims and evaluate actual particle reduction.

Misleading claims regarding air purifiers and home air purifier filters have in the past led to decisions and orders of the Federal Trade Commission against manufacturers, and are likely to do so in the future unless manufacturers practice better self-restraint and self-regulation.

Participating in sound business practices and making scientifically proven claims will restore lost faith in room air purifiers, allowing consumers to make informed purchase decisions - based not only on price but, also, on actual performance of home air purifiers containing HEPA air filters.

But alas, manufacturers of home air purifiers with hepa air filters don't give you the unbiased information due to their fiscal conflicts of interest.

Taking all of the above factors regarding home air purifiers and hepa air filters into consideration, we've concluded that there is a clear industry leader........Drum roll please.....here it is, the air cleaner with perhaps the best home air purifier filters.

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