HEPA is a technology created in the 1950’s and now regulated by the government. The acronym stands for High-efficiency particulate arrestance and according to United States Department of Energy standards, in order for a filtration system to be called ‘True HEPA’, it must remove 99.97% of particulate matter that is at least 3/10 of a micron in size.

There are basically two types of HEPA filtration systems on the market. The first type is the HEPA filtration system, which is listed just as ‘HEPA.’ This filtration system is effective at most of the particulate matter in your air, but it falls short on some of the smaller stuff. It filters 99% of particles that are 2 microns in size or larger. This gets mold spores and most of the dust mite allergens and pollen out there, but it doesn’t do everything.

The True HEPA filtration system on the other hand is a much better filter, getting rid of 99.97% of particles that are 3/10 of a micron in size or larger. You will be able to identify products that have types of filters, because they will always use the term ‘True HEPA’ somewhere in their advertising.

It is extremely important to choose a HEPA filter when you are installing a filtration system in your home or office. However, as explained above, there is a difference in the type of HEPA filtration system that you get. While HEPA filters will rid your air of 99% of particles 2 microns and larger, True HEPA will filter 99.97% of particles 3/10 the size of one micron and larger.

For most particulate matter, you can actually go a lot bigger and be fine with it, but you want something that filters as small of particles as possible, you want True HEPA filtration. Here is how effective True HEPA is with various types of contaminants.

Biological Contaminants: Removes 100% of germs, mold spores and pollen and nearly all dust mite and pet dander allergens.

Types of Dust: Removes everything but the smallest particles of suspended atmospheric dust.

Particulate Contaminants: Removes 100% of oil smoke, fly ash and cement dust and very close to 100% of smog, tobacco smoke and soot.

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Different Types

There is a great deal of variety when it comes to types of air filters and there is some crossover as well. These are the ten major types of air purification systems available today.


Portable air purifiers are the most common types of purifiers, and all of the systems listed above are portable air purifiers (they are also HEPA filtration systems, which we’ll get into in a moment). Many homes have forced air through their HVAC system and that usually incorporates a filter. For those homes that do not, or for HVAC systems that do not offer enough protection, the portable purifier is a good option.


The whole house air purifier is a filtration system that is designed to recycle the air throughout your entire home through a filter, HEPA in most cases, thus removing a great deal of the particulate matter that is in the air. Since these systems must move massive quantities of air through them, they are almost always tied into your HVAC system. A series of portable air purifiers in each room could qualify as a whole house air purifier, as long as each room, no matter how small, was covered.

A whole-house air filter is an option similar to the HEPA filtration system except that is simply passes the air through a filter – likely not a HEPA filter – and gets rid of the really big stuff.

Ion and Ozone Generators

The next type of filter that we are going to discuss is the category of ion and ozone filters. These filters are not the greatest type out there. They generate ions which does help to rid the air of impurities but they give off ozone gas a byproduct and while many of the types of systems listed here are approved HEPA filter air purifier systems, this is not one of them and is not recommended.

HEPA Filters

HEPA filters have been discussed in great deal already, so there is no need to rehash the same information. But just know that HEPA is pretty much the standard by which all other filtration systems are measured. Also, always keep in mind the difference between regular HEPA filtration and True HEPA filtration so that you can get the filter that actually removes what you want to get out of your air.

Activated Carbon Filters

Activated carbon filters are definitely not the only type of filtration system that you should have in your home, but they do make a really good addition to HEPA filters. The carbon filters use absorption to pull contaminants from the air which is very effective against odors, gases and vapors. Activated carbon is combined with all of the HEPA filtration systems that are listed above.

Activated carbon filters are often used with HEPA or other filters, and they pull impurities from the air through absorption. The oxygen in these filters creates openings to pull odors, gases and vapors. Those that contain the chemical chemisorbent can also pull VOCs. Activated carbon filters can be very effective in conjunction with other filters, as not all filters pull odors and gases along with the particles.

Electrostatic Precipitators

Yet another type of filter is the electrostatic filter, which as you may have guessed, uses static electricity to removes impurities from the air. However, these are pretty much in the same class as ion generators and produce ozone just as those do. Ozone gas can be a real problem if you already have any kind of respiratory illness and these type of filters are not really recommended.

Electrostatic precipitators remove impurities in the same manner as ion and ozone generators. However, they also filter impurities instead of just making them cling to a room’s surfaces. The particles are collected on a metal plate that can be cleaned. The disadvantage with electrostatic precipitators is that they produce ozone just like the generators. This can cause respiratory problems in anyone with a predisposition, as they can irritate the lungs.

Charged Media Filters

Another type of filter that produces ozone is the charged media filter and they are very similar in operation to electrostatic precipitators. The difference here is that these use actual filters instead of plates. The advantage is, they can filter out microscopic particles, but you have to change the filter and ozone gas is not a good thing to have in the air – especially if you have a respiratory illness.


Pre-filters are another crossover, as the filters that are listed above have carbon activated pre-filters that get rid of some of the odors in the air before the true HEPA filtration actually steps in and does its job. These are good filtration systems when used in conjunction with a true HEPA filter, and they are inexpensive to operate because instead of replacing the filter, you just have to wash it.

Antibacterial and Germicidal Filters

Finally, antibacterial or germicidal filters are able to get things that are too small to get trapped in the HEPA filtration system. An example of a combined true HEPA and antibacterial filter is listed above on the GermGuardian unit. Generally, they use UV rays to get rid of germs, bacteria and viruses.

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What To Know Before You Buy!

If you are considering a HEPA filtration system for your home or office, there are some things that you want to look for. This buying guide will help you to determine what to look for when buying and all of the factors that you’ll have to weigh when choosing yours. There are seven things to look at when it comes to choosing a HEPA air purifier.

Type of Filtration

When it comes to air purifier HEPA technology, there are two kinds. You want to be aware of this as you shop, and be on the lookout for the most effective kind – the True HEPA filter.

Room Size

You want to look at the specifications and see what size room the unit is rated to run in. Usually, they will give a rate of how many times the room air passes through the filter with the room size.


You want to try to find a HEPA filtration system that will allow you to wash or vacuum the filter a few times before actually replacing it, otherwise it is going to cost more for you to maintain the unit. The HEPA units on this list are some of the best HEPA air purifiers and they allow you to wash or vacuum the filter before replacing it, extending the life of your filter by many years.

Controls & Interface

You want to make sure that the controls are easy to use and what sort of features the unit has. For example, will it allow you to set a timer so that the filtration system goes on and off at specific times. If not, you will have to turn it off and on manually which can mean that your air isn’t filtered enough or you are running the unit too often and wasting electricity.

Aesthetics & Design

Aesthetics and design is not important to everyone, but if you have carefully decorated your home, you want something that looks as good as your other furnishings. Luckily, if you buy online, there are usually several pictures that will show you just what the unit will look like.

Noise Level

Noise level is also a consideration. If you put a noisy unit in your bedroom it may keep you awake. In addition to this, some units can have a bright light that will make darkening your room completely very difficult.


Finally, you are going to pay attention to price versus the value that you’ll get. Obviously, you want to pay the lowest price possible for the features and type of filtration that you need.

Other Important Features To Look For:

Some of the most important features of HEPA filtration systems are what they are combined with. You can have a True HEPA filter and be able to remove a lot of contaminants from the air, but most viruses are less than 1/10 of a micron in size – much, much less in fact – and the best HEPA filter in the world won’t be able to filter something that small. So, when you combine UV filtration to eliminate viruses and bacteria, you have a much more effective filter.

In addition, carbon activated pre-filters that are combined with a True HEPA filtration system will make for the best HEPA air purifier, because the activated carbon will help to remove odors form cooking, pets or even from cigarette smoke.

The second feature that is important, especially when it comes to buying online, is the number and rating of the reviews that a unit has. Checking customer reviews can give you a great deal of information before buying a product.

Are They Safe?

There is no reason to think that they are not safe. Although there have been isolated incidents with specific models of air purifiers where they caused an accident – usually dealing with an electrical issue – the vast majority of the HEPA filter units on the market have never had a problem.

As for the filtration itself, it is definitely safer for your health to get rid of the contaminants in the air. Some people view the bacteria and germs in the air as beneficial because it allows the human body to adapt and become stronger, but nearly all medical professionals are proponents of air purification systems.

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What is a HEPA air purifier? A HEPA air purifier is one that meets the government standards for filtering a certain size of contaminants from the air.

What’s the difference between an air filter and an air purifier? An air filter is just a unit that pushes air through a filter while a purifier combines other technologies like UV that do more than just filter the air.

What is the difference between True HEPA and HEPA? HEPA filters are rated to filter 99% of particles 2 microns or larger. True HEPA filters 99.97% of particles 0.3 micrometers or larger.

How much do they cost? The cost of a HEPA filter varies considerably, based upon brand, type and features, as well as where and when you buy it. Expect to pay $30 to $100 for low end models and $100 to $500 for high end models. Whole house air purifiers are much more expensive.

Can I filter my entire house with one? If you have a whole house air purifier installed with your HVAC system.

Does the filtration unit have any moving parts that might be dangerous to kids or pets? In 99.99% of cases the answer is no.

Does it give off any odors? Rarely and even if they do, these odors usually are only in the first few days of using it.

Where can I buy one? They are sold in department stores, home improvement stores and many other places but the best place to buy is online.

If you want cleaner air for your home, then a HEPA air filtration system is just what you need. HEPA filters remove nearly all of the contaminants from the air – contaminants that can cause asthma, allergies and other respiratory problems. But how do you choose the right HEPA air purifier to clean your home?

There are a lot of choices out there but we have reviewed a long list of systems and have come up with three that really shine.

Here are the three of the top HEPA air purifier systems on the market.

Best Overall
Best for Allergies
Best for Mold
Product Name:
GermGuardian AC5250PT
Honeywell HPA300
Honeywell 50250-S
GermGuardian AC5250PTHoneywell HPA300Honeywell 50250-S
Pre-Filter Type
UV-C Light
Max Room Size
442 sqft
465 sqft
390 sqft
Machine Size
9.5" x 6.1" x 27.25"
20.8" x 10.83" x 22.38"
18.0" x 18.0" x 19.6"

#1 –  GermGuardian AC5250PT – Best Overall (and for pets)

GermGuardian AC5250PT

The GermGuardian AC5250PT uses various combined technology to get rid of almost everything that you don’t want to be floating around in your air.

Our top pick is the GermGuardian 3-in-1 air cleaning tower, measuring just 28 inches but packing a huge punch when it comes to removing allergens, dust and other contaminants from the air.

  • Features True HEPA filtration
  • Includes Pet Pure Treatment technology
  • Charcoal filter
  • UV-C light technology with titanium dioxide
  • 5-speed 28-inch tower

When you want to clear the air inside your home or at work, you need a good air filtration system. This is definitely a good choice for your home because it will keep an entire room completely free of large particulate matter and help to reduce the toxins that cause allergies and other problems.

Having a reaction to the contaminants and toxins in the air is no fun, whether it is simply causing the itchy, water eyes and other symptoms of allergies – sometimes known as hay fever – or you have a predisposition to respiratory illness because of some preexisting condition such as asthma.

This is the best overall for a few reasons. There are a number of advantages that this tower unit offers that you won’t find collectively on most air purifier systems. For example, this purifier is equipped with true HEPA filtration rather than ordinary HEPA – a distinction that means that this filtration system captures smaller particulate matter and removes more contaminants from the air.

In addition, the GermGuardian 3-in-1 Cleaning System uses a proprietary technology called Pet Pure, which adds an antimicrobial agent to the filter itself to prevent mold from growing, eliminate mildew and get rid of bacterial that causes odors, including pet odors.

The charcoal filter that the air passes through before getting to the purifier also reduces odors from pets and cooking as well as the smell of tobacco smoke. Plus, since viruses are too small to be picked up by the filter, this unit uses UV-C light technology with titanium dioxide, which kills not only viruses but also germs, mold spores and airborne bacteria.

Finally, this is a tower purifier that works well with medium and large rooms, and amazingly with smaller rooms, with a CADR (Clean Air Delivery Rate) of 125+ depending upon room size, which is quite good.

There are a couple of issues with this unit. One thing is that you have to use Guardian replacement filters to keep the unit running at top performance and they can be a little expensive. Plus, sometimes, you have to replace the UV bulbs, and they also are expensive.

As far minor issues that have been reported – the blue UV light is very bright, especially at night. Plus, after a few months of use the plastic around the controls bubbles up. It doesn’t affect the operation through. Finally, the controls are not lit up at all so you have to turn on a light if you want to operate the unit in the dark.

There is a reason that this was chosen as the best overall filtration system – it works better than just about anything else on the market; it uses various combined technology to get rid of almost everything that you don’t want to be floating around in your air. If you want the best, click below to check the price on Amazon.

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#2 –  Honeywell HPA300 – Best for Allergies

Honeywell True HEPA Allergen Remover

You will definitely notice a reduction or complete elimination of your allergy symptoms with the Honeywell True HEPA Allergen Remover

This true HEPA filtration system from Honeywell is the absolute best for removing the allergens in the air that cause your symptoms.

  • Circulates air five times in 21×22 room size or smaller
  • Activated-carbon pre-filter
  • Removes up to 99.97 percent of particles from air
  • Captures many airborne germs
  • Helps capture certain airborne germs

If you have the sneezing, itchy, watery eyes and general feelings of discomfort caused by allergies, you know how advantageous having an air purifier for allergies can be. Allergies usually come during the spring or summer months when pollen and other allergens are heavy in the air. Having a filtration system like this can make a great deal of difference.

One of the advantages of this system over many of the others on the market is the true HEPA filtration rating that it features. A true HEPA air purifier captures smaller particles than ordinary HEPA, which means that your air is cleaner.

This unit also includes a carbon pre-filter, which means that the air passes through the activated carbon before it is actually filtered, reducing odors from smoke, cooking and pet smell. In addition, this purifier can be used in larger rooms and still be effective, circulating the air inside a room that is 465 square feet up to five times, and smaller rooms obviously circulate through the machine even faster.

The presence of allergens in your home is reason that you experience symptoms inside. Having a filtration system like this one can be a major advantage when it comes to battling your allergies and allow you not to worry as much about the air coming into your home, and whether or not it will make your allergies act up. In addition, it may help those who suffer from pet allergies have fewer symptoms.

Finally, a filtration system like this can help with other problems than allergies. For those with any sort of respiratory illness such as asthma that is activated by things in your air, a filtration system like the Honeywell is a benefit to their health and even helps protect those who do not suffer from either allergies or asthma.

There are a couple of problems that have been reported with this filtration system. One of the major disadvantages is the noise. This unit is pretty loud and if you have it in the bedroom running at night, you may have a hard time falling asleep at first, until you get used to the sound.

Plus, it would be nice if this unit had some kind of automated timer so that it would run each day for a certain amount of time or for a certain number of cycles automatically. Instead, you have to remember to turn it on when you want it to run and then turn it off later if you want to conserve energy.

Still the best air purifier for allergies hands down. You will definitely notice a reduction or complete elimination of your allergy symptoms with this purifier. Click below to see what the current price is.

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#3 – Honeywell 50250-S – Best for Mold

Honeywell 50250-S

If you are looking for a budget option that does a good job at filtration and you don’t mind the noise, this is still a better choice than most of the ones on the market.

Having mold floating around your home is a pretty serious problem. Mold causes a number of illnesses and can weaken your immune system. But this Honeywell purifier is the best purifier for mold currently available.

  • Features True HEPA air filtration
  • Long-lasting glass fiber HEPA Filter
  • Carbon-activated pre-filter
  • Doctor recommended
  • Intelli-Check electronic indicator

When it comes to mold in your home, there are two things that need to be done. First, you need to limit the presence of mold spores in your air with a filtration system like this one.

Mold is a very serious problem and breathing in certain spores can cause major health problems depending upon the type of mold – particularly if you have small children in the home or if you have one or more persons that suffer from some kind of respiratory condition.

Obviously, the second thing that needs to happen is to find the source of the mold and remove it. Of course, the main problem with that is that mold can hide in places that are difficult to look in like inside ventilation shafts or even inside ceilings or walls; that’s why preventing the spores from being inhaled should be your very first step.

This filtration system has a number of advantages over other comparable models. This model features true HEPA filtration, which is nothing unique when compared to the other filtration systems on this list but is something that many others on the market do not have.

In addition, this has a washable HEPA air filter. In this case, you vacuum it rather than wash it, and doing so can extend the life of your filter from one year to 3-5 years. This unit also includes the carbon filter that the others have, which is very effective at removing odors, and captures things like lint, dust and pet fur.

Finally, there is an indicator on the unit that tells you when it is time to replace your filter. Obviously, this is a big advantage when it comes to saving money, because if you replace your filter before it needs to be changed, you will be spending more than you have to. In this case, the light tells you when to clean your filters, which is really terrific, because you simply pull them out and vacuum or wash them and then replace them without spending any money.

The main disadvantage of this filtration system is the noise – it is really loud and even if you are sleeping a room away you might still hear it. Plus, if it does happen to be in the same room as you, there is a bright light on it that you cannot turn off, which can make it hard to sleep for those who require complete darkness. Of course, there is also the disadvantage that it doesn’t work as well as the other two on this list.

If you are looking for a budget option that does a good job at filtration and you don’t mind the noise, this is still a better choice than most of the ones on the market. However, the others on this list are better options if the price isn’t that important. Find out right now if this item is on sale at Amazon by clicking here.

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