Air Filter vs. Hepa Filter?
Which one is better?
I know that hepa filter is good for people with allergy as well as water filter (but it requires replacing water). What would be better and what are the dis-advantages for both of them?
Categories: Hepa Air Purifiers Tags: filter, Hepa
Both the systems are intended for removing the allergens (allergy causing substace’ particles) from the air. Depanding on your budget and type of allergy you should select the one.
For dust related allergies HEPA are better where as for chemical fumes or smokes water based filters are best.
Please check the details given below to have the clear idea.
Both the filteration techniques are the Ozone-free air cleaners used to to address the allergy and asthma symptoms, Multiple Chemical Sensitivity (MCS) and air quality issues such as pollution, cigarette smoke and construction dust.
There are several basic technologies that are known to be effective in providing real improvement to office and home indoor quality. These are HEPA air purifiers and electrostatic air cleaners that typically also use activated carbon and sometimes UV purification.
HEPA filters effectively remove 99.97% of all particulates such as pollen and dust that pass through the filter, returning purified to your home or office. HEPA filter technology is among the best technology available for air cleaners. It is a very effective system but the filters must be changed to remain effective. Electrostatic or electronic systems by Friedrich clean with charged plates and save the cost of replacement filters but requires that the plates be washed. Both of these main technologies remove particles but not chemicals or odors. To address this need, room air purifiers must also have some form of activated carbon from as little as a thin mat to as much as 15 pounds. UV is also sometimes employed with a HEPA filter to eliminate microorganisms.
Air Purifier Technology
Air purifiers employ what seems to be simple technology on the surface. Effective air purifiers draw from the room with a fan, clean the air, and send it back out into the room. There are a number of ways cleaning is performed while in the actual system. First there is adsorption. Adsorption uses a media like activated carbon or zeolite. These medias are porous so that the airflow is exposed to relatively large surface area. As the chemical contaminates come in contact with the media the chemicals combine the media and are thus removed from the room. Adsorption will remove chemicals and some parts of tobacco smoke and odors but has little impact on particles. The second approach is mechanical filtering much like your furnace filter. In this case the room air is screened of particles however, the screen is very fine. An example of a very fine screen is a HEPA filter that removes particles as small as 0.3 microns. While air purifiers that use HEPA will remove particles like pollen and mold spores they has little effect on chemicals so this technology is typically used in combination with some form of adsorption filter. The third effective technology for air purifiers is electrostatic or now also known as electronic. These air cleaners use charged plates to give particles a charge of one polarity, positive for example, and a set of collecting grids or plates that have the opposite electronic charge, negative for example. As the charged particle nears the collecting grid it is drawn there by opposite charge on the collecting plate. As the particles build on the collecting plates the charging voltage will start to arc causing a popping sound. This is when you know it is time to clean the air cleaners plates in the dishwasher. Another effective albeit unique technology is a hybrid between HEPA and electronic. Blueair Air Purifiers uniquely use electrostatic brushes to charge the particles prior to being mechanically filtered. This allows the Blueair air purifiers to use HEPA with larger holes and thus get higher throughput. While not strictly a cleaning technology, in the strictest sense, we will address Ultra violet or UV light here. UV is a light that kills microorganisms such as bacteria and mold spores. This is always used in conjunction with other technologies employed in an air purifier.
Most all of the high-end air purifiers use some type of pre filter in addition to the filter elements mentioned above. The purpose of pre filters in air cleaners is to extend the life of the fine filter such as a HEPA element by removing large particles before they can get to the HEPA filter. You will typically find visible dust, hair, and lint in the pre filter. By keeping the pre filter clean you can dramatically extend the life of your HEPA filter and improve the overall efficiency of your air purifier.
The above discussion is focussed on effective systems and specifically ignored air purifier technologies that use or produce detectable levels of Ozone or other non-fan based technologies. These are generally bad for you.
Office and Home Air Purifiers – Efficiency:
Efficiency refers to the amount of air that is actually passed though the filter system of an air purifier. While a high grade air purifier HEPA filter will filter out 99.97% of the particles that are 0.03 micron and smaller this only takes place in the flow that actually passes though the HEPA filter. In typical home improvement store brand air purifiers a good percentage of the flow slips by the filter system and is propelled back into the room without being cleaned. Unfortunately the manufacturers are not required to state their air purifier efficiency. IQAir Air Purifiers is the only company that states that better then 95% of the flow that enters their air purifiers is cleaned and returned to the room.
The information on internet, based on reports from various customers, says that the high end metal frame air purifiers from Blueair and Austin Air purifiers are also very efficient.
Applications of Air Purifiers:
The real key to addressing any Indoor Air Quality (IAQ) issue is the removal of the source of the pollutant or irritant if possible. One has to understand that if you love your cat to which you are allergic you have to deal with the dander but, if you are allergic to mold spores your first step is to either remove the source yourself or have it addressed professionally. Secondly, if you have a whole house forced air system you need to make sure that your system is well maintained and that the filter is a high quality one that is changed regularly. Now that you understand the basic types of air purifiers and the ground rules for IAQ you can address air purifier applications.
Asthma Air Purifiers – This is a tough medical condition with which to deal and we can only address the asthma that is induced by poor air quality not that induced by exercise or stress. The asthma triggering irritant may be either a particle such as pollen or a chemical or smell. Therefore, we must utilize both mechanical and adsorption air purifier technology. This translates to HEPA and activated carbon air purifier media. The top of the line air purifiers that include both is the IQAir HealthPro Plus. Other good choices are the Austin Air Purifier HealthMate Plus or HealthMate Plus Junior, the Blueair family, or the Allerair VoCarb air purifiers. If there is no concern about chemicals or odor then the electronic Friedrich C90B can also be considered. It is excellent at removing particulates such as pollen and dust.
Multiple Chemical Sensitivity (MCS) or Chemical Allergies – For these issues we cannot emphasize enough the elimination of the source of your sensitivity. While air purifiers will help, the constant irritant will increase your sensitivity. After you have addressed the source, the air purifier technology that will be of primary importance is adsorption. There are a number of models that specifically address MCS. The IQAir air purifiers; GC VOC, GC Multigas, and GC Chemisorber are designed to address specific chemical adsorption. Other manufacturers of air purifiers that address these issues include the Austin Air Healthmate Plus series includes highly absorptive potassium iodide to address MCS and Allerair VoCarb air purifiers.
Pollen, Dust, and Mold Allergies – This is one of the most common applications for home air purifiers. All of these pollutants can be classed as particle pollution and can be handled by two of the air purifier technologies we discussed above; HEPA and electronic filters. The Friedrich C90B is excellent in addressing these irritants and has scored very high in third party tests. The IQAir HealthPro air purifiers, Austin Air HealthMate and Austin Air HealthMate Junior, Blueair Air Cleaners models, Allerair Exec, and Air-O-Swiss HEPA air cleaners are also effective at removing particles. If smells or odors also tend to trigger your allergy then you should consider using the air cleaners recommended for addressing the symptoms of asthma.
Pet Allergies – Since we are assuming you will not get rid of your pets we will emphasize the cleaning of their bedding and other items such as toys and play gyms to reduce the source of the pet material as much as possible prior to installing any air purifiers. Pets, particularly cats, tend to clean themselves by licking their fur. This leaves a very fine film of saliva on their fur that dries and then goes airborne as a very fine dust. This is the primary cause of most pet allergic reactions. While this represents a mechanical pollutant and would indicate that HEPA or electronic air purifiers were used we have found that our customers are happiest if chemicals or odors are also addressed, particularly if the pet is a large dog, like a Lab, that will exude that wet dog smell on rainy days.
Tobacco Smoke – The smoke from cigarettes and, even worse, cigars is a stew of gasses and particles. It is particularly hard to address with room air purifiers because the source is so active putting out so many pollutants in such a short time. Even if all of the room air went though the air purifier 6 times per hour a Cigar will still overwhelm the air purifiers until it is extinguished. If you are unable to