Air Purifier FAQ
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Air Purifier Frequently Asked Questions (FAQ)

Here at, we received tons of air purifier questions that you probably can relate to. From how air purifier works, types of filters, functionality, allergies and symptoms to product recommendation. While we are happy to answer all of your questions, from time to time we do missed out a few due to the sheer numbers of emails piling up. To give everyone a quicker and more up-to-date response, we compiled a list of frequently asked questions by our reader along with answer and recommendation as well. The list will be updated regularly so feel free to drop us a comment or question if you did not find the answer that you need.

Air Purifier

What is the differences between a HEPA Type VS True HEPA filter? Which type of HEPA filter is better at capturing airborne pollutants?

The major differences between HEPA Type VS True HEPA filter are the filtration efficiency. In general HEPA type filter has a 99% efficiency capture rate of particles as small as 2 microns (dust, hair, pet dander, pollen). True HEPA filter up the game with a better 99.97% efficiency capture rate of particles as small as 0.3 microns (allergen, bacteria, virus). As both mechanical filters are widely used in the air purifier industry, HEPA-type filter is often pair with cheaper, compact air purifier while True HEPA is more than likely tag with the bigger, premium air purifier. As for filter longevity, you will often find HEPA type filter with a longer lasting, or permanent lifespan (washable) while it’s almost impossible to associate it with True HEPA filter. Both types of filters can trap virtually any indoor airborne particles however, if seasonal allergens and bacteria is your main concern, an air purifier with True HEPA filter is the one to go for.

In short True HEPA filter is the upper version to HEPA type filter with a standard 99.97% capture rate down to 0.3 microns size VS 99% capture rate at smallest 2 microns. Both filters can trap virtually every type of airborne particles however, if seasonal allergens and bacteria is your main concern, air purifier with True HEPA filter is the one to go for.

I seen quite a few filters listed here that is either washable or reusable. What is the differences between them?

Not much as here in, we associate both under the same category. Washable/ reusable air filter is a type of filter that can be use multiple times through simple vacuuming or rinsing. Commonly found in permanent pre-filter that does not infuse with charcoal or activated carbon, HEPA/ carbon filter is typically not washable/ reusable with a few exception of air purifier with permanent HEPA filter (limited through light vacuuming). Soaking a HEPA or carbon filter through water could potentially damage the filter functionality. Always refer to the instructional manual to check if the air filter is reusable/ washable.

So in general, reusable/ washable air filter is the same and is typically found in permanent pre-filter without any deodorization feature. Most non-permanent, HEPA/ carbon filter is not reusable and has a limited lifespan. you are looking for an air purifier with long-lasting filters, we recommend browsing through our air purifier with permanent filter list.

I heard of the danger of VOCs and was told that an air purifier can effectively remove it in from our home. Is it true?

Yes, air purifier can be effective against VOCs but the prerequisite requirement is to have an activated carbon filter in its filtration. Volatile organic compounds (VOCs) is an odorless gas made from variety of chemicals e.g. Benzene, Toluene, Formaldehyde, Ethanol. Evaporate from our daily household products such as paint, detergent or plastic, exposing VOCs to our body would have short to long-term adverse health effects from eyes nose irritation, headache, dyspnea, nausea, fatigue to the more severe kidney, liver and central nervous system damage. The solution? Identify and remove VOCs based product is a good start while increasing the room ventilation is another immediate solution. Air purifier with advanced carbon filter is a non-organic solution that can capture different micron sizes of airborne gas based particles. Specialized chemical air purifiers that comes with additional filtration or ionizer is a clear indicator of good VOCs air purifier that would effectively reduce the VOCs level in our home.

To sum up, air purifier equipped with advanced carbon filter can eliminate strong chemicals like VOCs. For the best result choose specialized chemical air purifier that focus on household chemicals and smoke based particles.

People keep saying dust is bad. What harm can a little dust do?

Inhaling large amount of dust would have adverse health effects especially to our lungs. Dust is made out of many different type and size of particles from hair, pet dander (dead skin), pollen, bacteria and viruses. In short run, inhaling small concentration of dust would often lead to symptoms like red eyes, cough, hayfever and sneeze while in long run it could reduce the lung capacity or cause chronic bronchitis and heart disorder. People with chronic obstructive airways disease (COAD), emphysema or asthma would be at a higher risk. While it’s impossible to stay in a dust-free environment, stay away from dusty area or regular house cleaning/ vacuuming is the basic step to do. The alternate solution is to equip your home with a reliable air purifier that can run 24x7. Most air purifiers in the market has the capability to filter out large amount of airborne dust within its purifying radius. Higher range air purifier would be able to capture even the tiniest particles and substances that tag along with it.

In short, air purifier can effectively remove airborne dust and all the tiny particles attached to it. For the ideal dust removal machine, please go to our best air purifier for dust page.

I am suffering from seasonal allergies and to make matters worse I stay close to nature surrounded by many trees. Can air purifier get rid of pollen/ spore/ mold once and for all?

Air purifier can get rid of airborne mold/ mould plus any associate allergens and toxic substances released. Inhaling or exposing to mold could lead to adverse health effect and trigger the infamous asthma attack. If you are tested or suffering from symptoms like cough, wheezing, chest tightness, nasal congestion, irritation on eyes, skin or throat, an air purifier would serve as a great reliever. Furthermore, an air purifier with antimicrobial treatment can stop the microorganism from further growth including those that are trapped within the filter. For a complete mold-free environment, regular housekeeping is require as air purifier cannot capture existing mold stuck on the ground or wall. As mold thrive on high humidity area, we recommend using a dehumidifier alongside an air purifier to maintain the room humidity at an ideal level.

To recap, air purifier is very effective against seasonal allergies/ hay fever up in the air (airborne). To help you choose the best air purifier for the job, please go to best pollen, spore, mildew, mold air purifiers page.

I am confuse between an air purifier, humidifier and dehumidifier, which model should I buy to improve air quality?

Air purifier or air cleaner would be the straightforward choice as it help improve IAQ (indoor air quality) via the removal of airborne particles like dust, mold, pollen and pet dander. Air purifier can also remove toxic smoke and odors from cigarettes while air purifier equipped with True HEPA filter can further eliminate harmful virus and bacteria that cannot be seen through naked eyes . Dehumidifier would assist in improving indoor air quality by reducing excessive moisture level in the room to stop microorganism like mold from growth. On the other hand, humidifier would increase moisture level in the room so it is more liveable. Dry air would often lead to symptoms like dry throat, cough or flaky/ itchy skin.

In a nutshell, all 3 models would help improve indoor air quality however, air purifier is the obvious choice as it directly improves air quality by removing airborne contaminants. Humidifier would increase moisture level in the room while dehumidifier does the opposite by decrease moisture level.

I am suffering from eczema and desperately trying to find the root cause to it. Can air purifier actually treat eczema or other skin related diseases?

Yes air purifier can help with eczema but only to a limited extent. Also known as dermatitis, eczema is a chronic skin disorder where the skin becomes cracked, red inflamed and intensely itchy. Often caused by dry skin, food we consumed (milk, egg, gluten, nuts, fish, soy based product), scratching (due to itchiness), sensitive skin and poor air circulation. An air purifier can help with the last part by capturing eczema link allergens like mold, spores, pollen and bacteria. With all unwanted airborne particles captured, air purifier would then distributing and circulating clean, filtered air in your home.

To summarize, air purifier can help in relieve and reduce eczema from flare-up, but it cannot do it single-handedly. Applying cream, selective food or using a humidifier would be a higher priority option in dealing with eczema.

I own both air purifier and a dehumidifier model. Can I run both air purifier and dehumidifier at the same time in a same room?

There is no conflict in running air purifier and dehumidifier at the same time as both function differently. Air purifier is the unit to go for if you have concern on allergies and other common symptoms like sneezing, coughing. It circulates clean air by capturing airborne irritants and gases e.g. dust, pet dander, pollen, mold, smoke and odor. On the other hand, dehumidifier absorb moisture from the air that stop microorganism growth and maintain the ideal room humidity level. Microorganism like mold requires a high humidity environment to thrive. In that sense both air purifier and dehumidifier would help reduce the number of airborne irritants and allergies that is associate with it. One word of advice is not to place both air purifier and dehumidifier side by side as there could potentially be obstruction in the airway. The heat generated from dehumidifier could also damage the air purifier’s filter.

In short, you can run both air purifier and dehumidifier at the same time as both models have different purpose and functionality.

Just brought a * air purifier and I was wondering how long does it take to clean a room at around 300 sq. ft.?

On average most air purifier would take 30 minutes to 2 hours to completely cover an entire room. Highly dependent on the fan speed, room size and the air purifier’s purifying coverage, the air purifier first must have the capacity to fullfill the room size. An estimated 300 square feet room size would need an air purifier with at least 300 square feet of purifying coverage. Parallel with the purifying coverage, an air purifier running in 4 speed would take only half of the time covering a room then the same air purifier running in 2 speed. To get the best out of the air purifier, we recommend running the unit at full speed for at least couple of hours and switch back to lower speed to maintain the room quality standard. You should also keep your air purifier running 24 hours a day as dust and other airborne particles circulate throughout the day.

In short, expect 30 minutes to 2 hours for an air purifier to clean a room. To get a better estimation on the time needed to cover a room, you would need to factor in the air purifier’s purifying coverage, room size and fan speed the unit will be running.

My air purifier is not performing well which I suspect is because of the accumulated dust in it. How do I clean the air purifier filter?

Depends on the type of air purifiers you are working with, most air purifier filters are cleanable but only through vacuuming or with a soft brush. First thing first, always turn off and unplug the air purifier before performing any cleaning. Gently remove the cover panel and remove the filters one by one. As a general guideline for clearing away filter’s dust, standard permanent pre-filter can be vacuum or clean with warm, soapy water. Most 2-in-1 carbon pre-filter, permanent filter, HEPA filter and carbon filter can only be clean through careful vacuum on the pleated layers. There is specific HEPA/ carbon filter that require interval replacing rather than cleaning due to the relatively short lifespan. Do not use household cleaners or detergents to clean any of the filters. Also, never place filter into a dishwasher unless specifically stated in the manual. If you notice the filter is worn out/ damaged to the point of beyond cleaning, replace the filter. Finally as an added bonus point, keep the air purifier's airflow inlet/ outlet clean to prevent dust from compiling on the air ventilation. Finally, repeat the above steps every 1 – 3 months or when the filter clean/ indicator lights lit up.

You should see an instant improvement on the air purifier airflow performance. To recap,

  1. Turn off and unplug the air purifier before anything else.
  2. Most permanent pre-filter can be vacuum or clean with warm, soapy water.
  3. Most 2-in-1 carbon pre-filter, permanent filter, HEPA/ carbon filter can only be clean through vacuuming while specific HEPA/ carbon filter only require interval replacing.
  4. Never not use household cleaners, detergents or dishwasher to clean the filters.
  5. Replace filter instead if is worn out or damaged.
  6. Clean the air purifier's air ventilation.
  7. Repeat steps every 1 – 3 months or when necessarily.

I am hypersensitive to all kinds of allergies from the common dust to the irritating pet dander. Can air purifier manage or better yet suppress my allergic reaction?

Yes air purifier can help with your allergies but it's only limited to airborne irritants. Household airborne particles like dust mite, pollen, mold, spore and pet dander is often the first line of triggering point to any allergies including asthma. Often irritating than deadly, every time we inhaled these airborne irritants, our body will react with symptoms like wheezing, sneezing, coughing, nausea, red eyes and even headache. What air purifier does is simple, it will effectively remove any airborne particles and allergens before we inhale it into our lungs. With clean air achieved, you will breathe a lot easier without any of the pesky irritants lingering around. The only requirement need from your side is to pick the right types of air purifier for the specific allergens you are dealing with. Again, do keep in mind that anything that falls into the ground will not be capture by an air purifier. It is advisable to also vacuum/ clean your home regularly to help build an allergy-free environment.

In summary, air purifier is only part of the solution to your typical allergies woe. Picking the right type of air purifier and regularly cleaning your home is the perfect combination solution.

I am allergic to pets, more specifically cats which I can't stop sneezing when they are around. Can air purifier help with my allergies?

Yes air purifier can get rid of pet allergies like pet dander, fur, germs and bacteria. As pet allergies can developed over the course of our lifetime, it’s heart breaking to see people giving up on their pets due to the severity of their allergies. Fortunately there few solutions that could work and air purifier is one of them. In order for an air purifier to work, you would need to choose the right types of air purifier. First the air purifier must have HEPA filter or other similar type filtration. UV-light, Ionizer would work as well but it’s simply not as effective as HEPA 99.99% filtration efficiency. To make things easier, look for specialized pet air purifier or air cleaner with pet targeted filter. Secondly, the air purifier must have enough purifying capacity and coverage to cover the constantly flowing pet irritants. A compact air purifier with limited coverage would take ages to clear out all airborne particles. Thirdly, clean/ replace the air purifier filters routinely or when necessarily to achieve the best filtration result. On top of it all, regularly vacuum pet fur stuck on furniture/ floor to reduce the fur from re-floating back up in the air.

To roundup, air purifiers do work for pet allergies but make sure the air purifier is fitted with a reliable filter like HEPA, solid airflow performance and purifying coverage. For the ultimate pet air purifier, check out our best air purifier for pet allergies and odors page.

What are the things I need to take note if I plan to use my air purifier throughout the day. Is it possible for an air purifier to be energy-efficient?

In general most air purifier is very energy-efficient as the energy consumption is around the same rate as a lightbulb at LOW speed (keyword: LOW). Keep in mind that air purifier is require to be ON 24x7 to achieve the best possible result, so here are some few energy saving tips that you can practice to get the most out of an air purifier. First and foremost, choose the right air purifier that would cover the right room size. Lookout for ENERGY STAR rated model which will be added bonus point. An air purifier that does not fulfil the purifying coverage would take ages and higher speed to cover an entire room. Never place an air purifier too far from the room as you will need higher fan speed to reach the intended target. Remember higher speed = higher power consumption. Another tip that most people forgot is keep your windows and windows shut when your air purifier is in operation. This will block out any external pollutants thus reduce the workload of an air purifier. A good ir purifier does not need to operate at MAX speed all the time. Always start with highest speed for couple of hours and tune it down to low speed to avoid the unnecessarily energy usage. To avoid all the above speed adjustment hassle, choose an air purifier that comes with Auto mode as standard and let it works its magic. Lastly always clean or replace the filters accordingly to maximize the air purifier filtration efficiency without resorting to higher fan speed.

To summarize, air purifier can be energy-efficient at low speed. First choose the right model that has enough purifying capacity to cover an entire room. Look for ENERGY STAR Rated logo. Place and direct the air purifier as close to the intended target as possible. Keep windows and door shut whenever is possible. Activate Auto mode if the feature is available or manually adjust the speed to the highest setting for couple of hours and set it to low throughout the day. Always replace filter according to its usage lifespan or when necessarily.

I live in a damp environment thus you will often see the growth of mold. Can air purifier get rid of mold in my house?

Air purifier can help with mold issue but only to the certain extend of airborne. Mold might not be as toxic as many online channels made out to be, it does have adverse health effect on human body and cause irritation like itchy skin, throat, coughing, wheezing, stuffy noise, fatigue, joint pain, watery eyes. Airborne mold that is not dealt with would eventually fall to our cloths, furniture or floor if not taken care of. A “right” air purifier would effectively kill mold spores in the air within it's designated zone. You could either go with UV air purifier, Ionizer or HEPA air purifier (True HEPA or HEPA type) which by far is the most common and effective method by trapping them in a dry mesh filter. To get rid of existing mold on your tiles/ wall, use either mold remover products or natural remedies like vinegar. To reduce the numbers of mold growth, use a dehumidifier to control the moisture level in your house.

In short, mold thrive on moist environment. Air purifier can only remove airborne mold, dehumidifier would reduce the growing numbers of mold in your house and any existing mold on the wall, tiles would need to be clean up manually. Visit best air purifier for mold page for our hand picked recommendation.


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