Are Air Purifiers a Waste of Money?


Air purifier brands make very promising claims about improving indoor air quality.

But are these claims actually true or are purifiers just a waste of money? The short answer that air purifiers are effective and worth buying. Usually, it’s when people buy an air purifier with a capacity that’s below their room size that they think an air purifier is a waste of money. But as long as you choose one with the right filters and a powerful enough airflow and capacity for your room size, an air purifier can clean the air in an average room in less than half an hour each time you use it.

So let’s talk about air purifiers and what you need to pay attention to so that the one you buy is worth your money!


How Do Air Purifiers Work?

Generally, air purifiers use fans or blowers to draw air inward and then pass it through air filters. The filters are usually a combination of several layers.

A mechanical filter first filters out larger particles.

Then, usually the remaining air will pass through more specialized filters. We recommend air purifiers with activated carbon filters and HEPA (High Efficiency Particulate Air) filters. HEPA  filters are more than 99.7% effective in removing the particles up to the size of 0.3 microns. Read this post if you’d like to find out more about what kinds of particles a HEPA filter can remove.

Air purifiers can either be portable or stationary. Portable air purifiers, which is what most people use, can be used in individual rooms and moved around to be plugged in somewhere else as needed. Large air purifiers can be used with central HVAC systems and are built into the duct work. It can give you powerful filtration for your entire home rather than having to have a portable air purifier for each room. 

According to the EPA, these built-in air purifiers may not be able to remove every contaminant from your room  but it can give a very good filtration and reduce air pollutants when used along with an HVAC  system. 

Recommended Reading:


Similarities and Differences between HEPA Filters and  Activated Carbon Filters

HEPA filters can remove almost all the contaminants from the air that are up to 0.3 microns in  size. They can filter numerous microorganisms including bacteria, mold, dust mites and pollen. 

On the other hand, carbon or charcoal filters are generally designed to remove odors, smoke, fumes and chemicals from indoor places. These are usually pollutants that are smaller in size. Activated carbon achieves this by its uniquely porous surface area.

Ideally, you should use both HEPA and carbon/charcoal  filters to improve the indoor air quality of your bedrooms, offices, class rooms and other indoor  places. Be careful of manufacturers that don’t use true HEPA filters.

Those filters are often advertised as “HEPA-like” and claim to remove 99.0% instead of 99.7% of certain pollutants that are typically slightly larger than 0.3 microns in size. While this might just be a nuance to most people, what it really means is that it leaves a lot of particles unfiltered. It’s best to stick with true HEPA filters.


How Often Should You Run Your Air Purifier?

For larger spaces, you’ll need to run the purifier for more extended periods. Smaller rooms  generally take less time to clean. We recommend that you run the purifier at regular intervals so that lingering pollutants don’t accumulate. To get the best results from your air purifier, consider  pairing it with an air quality monitor.

Recommended Reading:


Benefits of Air Purifiers

Lower the Risk of Allergies and Asthma

An air purifier reduces contaminants and pollutants from indoor air which may trigger some  allergies and asthma attacks. These pollutants include: 

  • Mold 
  • Pollen 
  • Dust particles 
  • Hairs of your pets 
  • Particles of home cleaners 

Air purifiers prevent asthma symptoms and allergies by filtering out airborne allergens like pollen,  dust, and animal dander. However, they do not cure asthma and allergies. Purifiers are more of  a preventive measure; not a cure. 


Get Rid of Bad Odors

If your home possesses persistent odors of things such as smoking, cooking and detergents which are tough to remove, then installing an air purifier will solve the problem.


Protection Against Airborne Germs

Air purifiers with HEPA filters are capable of removing many germs which may include a variety of bacteria, fungi and viruses, as long as there is also a heavy activated carbon filter attached.


Get Rid of Pet Dander

Ridding your indoor air of pet dander and odors is crucial, especially when you love your pets.  Pet dander consists of several allergens that aggravate sensitive immune systems, including pet  saliva, dead skin cells, and even outside particulates brought in by your pet on their coat.

These factors or allergens trigger those allergies and, more often than not, are dispersed throughout your indoor air and on furniture. The good news is that compared to smoke and microbes, pet dander as a pollutant is relatively average in size and can easily be picked up with an air purifier with just a HEPA filter.


Solve Other Issues Related to Poor Air Quality

In case you or anyone in your home do not experience any allergy or asthma, there are a number  of other health related issues which can be caused by polluted air. Poor air quality plays a  significant role in your overall health issues which may include:

  • Itching in eyes
  • Sore throat
  • Hair dandruff
  • Psychological disturbance
  • Coughing and sneezing

The above described issues can be or cannot be due to poor air quality. In order to assess your health linkage with poor indoor air, observe your symptom differences inside and outside your home. If  you experience any of the above symptoms more often inside your home, then it is due to poor  indoor quality which creates the need for an air purifier in your home. An air quality monitor can also help give you specifics so you know for sure.


Important Factors to Consider When Buying an  Air Purifier

Following guidelines must be kept in mind if you are investing in your health by buying an air purifier:

  • Avoid ozone producing filters. Ozone can be problematic for your lungs and throat. EPA also emphasizes to skip ozone producing purifiers.
  • Always go for HEPA filters and skip regular air filters. HEPA filters are most beneficial for essential purification tasks such as removing dust aerosols, chemical droplets and germs.
  • While buying an air purifier, think about your entire home. You’ll probably find that it isn’t enough to just buy one portable air purifier for one area, but rather that your entire home has several areas that each need their own air purifier. Or, you can always also get a whole house air purifier that’s part of your HVAC system.
  • Don’t be afraid to get technical – you’ll need to know CADR, ACH, and CFM to properly size your room’s air purifier – we’ll discuss that next.


Some Basic Technical Terms Associated with Air  Purifiers

What does CADR stand for and Why is it important?

CADR stands for Clean Air Delivery Rate and is a critical factor to assess the efficiency of an air  purifier. The Association of Home Appliance Manufacturers has developed this indicator to  calculate the volume of filtered air delivered by an air purifier.

The CADR value of an air purifier is given for three types of pollutants – pollen, smoke and dust. Essentially, the CADR number tells you the size of the room (in square feet) that the air purifier is intended to be used for. It assumes 8-foot ceilings, so you’ll need a higher CADR rating if your room has high ceilings.

The higher the CADR value of an air purifier, the larger the room it can be used for is.


What does ACH stand for and What is the recommended  ACH rating?

While CADR determines the volume of a space, it doesn’t say anything about how quickly the air can be moved and filtered.

This is what ACH does.

ACH stands for Air Changes per Hour and is an important factor to determine the filtration capability of an air purifier. ACH is basically the indicator that shows how frequently an air purifier filters or replaces all of the air in a given space per hour. For example, if an air purifier has an ACH rating of 6, that implies it will complete its filtration cycle six times in an hour, or once every 10 minutes.

Typically, an ACH of rating 5-6 is recommended for healthy indoor air in a bedroom, office, etc. However, if there are individuals with allergies and asthma, then an ACH rating of 6-8 should be preferred.

If in doubt, always try to get an air purifier with as high an ACH as possible. While it’s impressive to claim to filter out all the air in a room every 8 to 10 minutes, this information should be taken with a grain of salt. ACH measurements are done in laboratory settings with no human interference, but your home is made up of a lot of factors and obstructions that lower air flow.


What does CFM stand for and How to Calculate it?

CFM stands for Cubic Feet per Minute and is another useful measurement to determine the filtration capability of an air purifier. It essentially tells you the power of the air purifier.

A CFM value indicates how many cubic feet of air move through an air purifier per minute. An air purifier will have better efficiency if it has a higher CFM value.

Remember, several factors may affect the CFM value of an air purifier including fan speeds, insulation, air flow in the room, furniture, and the amount of pollutants in the air.

However, you can use a simple mathematical equation to determine an ideal CFM of an air purifier for a specific indoor space. This value can be found by calculating the total volume of your space (length x width x height in cubic feet) and divide this number by your desired ACH.


Air Purifier Maintenance

If you already have an air purifier, it’s important to check on it every so often.

The filters will need to be cleaned and changed regularly. So, how much maintenance is required for the air filters?

The lifespan of the filters varies, depending on where you live, the manufacturer’s recommendation, and the frequency of use. In reality, there is no “one size fits all” when it comes to knowing when to replace an air purifier as each is different. Most air  purifiers have two to four filters.

For the majority of air purifiers, filters should be cleaned occasionally and changed every three to eight months, depending on the model purchased. The activated carbon filter is typically changed most frequently, while the HEPA filter is changed less often.

Some models also have permanent air filters that never need changing, but need to be washed regularly.


Related Questions

Are There Any Side Effects of an Air Purifier? 

Generally speaking, there are no side effects of air purifiers. However, there are a few purifiers on the market that use electrostatic precipitators and ionizers; these may emit small levels of ozone. Make sure to do your research when buying one.


Is it expensive to use an air purifier? 

It depends on the size, frequency of use, and power use of your air purifier. Here’s a helpful resource that can help you calculate your monthly electricity bill before you purchase one: How Much Electricity Does An Air Purifier Use?