How to Choose an Air Purifier, According to Science – 9 Factors to Consider

Buying an air purifier for the first time? Don’t worry, this guide will get you to ask the right questions for your ideal air purifier. 

Air purifiers can be used for many purposes - dealing with allergies, improving indoor air quality, to get rid of pollutants (especially when you have children and pets at home), and more.

Air purifiers remove pollutants, dust, pollen, and pores from the environment. But the most important thing to remember is that air purifiers purify - but do not clean - the air. Careful consideration of the factors we identify below is important so you don’t breathe in other harmful gases or volatile compounds that may come from the air purifier itself.

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All this said, you’re now probably wondering what these factors are. So let’s begin!

1. Think Over Your Budget

Determining your budget before you decide to choose the right kind of air purifier is essential. Buying the best air purifier might cost more money than anticipated, so knowing what’s the market value of standard to professional air purifiers will definitely help you.

This also includes operating cost as well as the price tag of air purifiers. The operating cost of any extensive portal models depends on usage. A recent report that evaluated people’s willingness to pay for air purifiers showed that those who can afford to invest in a higher-priced air purifier for cleaner air will do so unquestionably. (1)

It also evaluated that an average person would pay $5.50 to remove a single microgram per cubic meter of pollution from their indoor space. And for a higher-income buyer, $15 per one microgram per cubic meter of pollution. Frankly, this says a lot!

Reliable air purifiers cost from $20 to a lot more than $1000. If you’re able to find a reliable and durable air purifier for a price that falls between these margins, you don’t have to spend an exorbitant amount on expensive ones. That said, equating price with quality is not always the way to go. So considering the following factors along with price is important for most buyers out there.

This brings us to the next, also significant, part of the process of choosing an air purifier. It’s the operating cost of an air purifier. Picking the best air purifier may seem expensive initially, but if it runs highly efficiently can help you save significant ongoing costs down the road. Factors such as the ability to replace or clean the filter and the dust reduce the operating cost you have to incur during professional repair.

According to Consumer Reports, a typical filter changes costs between $10 each up to $100. And based on the shelf life of each carbon filter, replacing them once every three months is considered healthy. (2)

2. What Are The Different Types Of Air Purifiers?

Air purifiers aren’t complex machines, as some of you might think it is. It is available in the most standard shape and size, but if you want better functionality and versatility, you can opt for any one of these different air purifier technologies.

Here are the most common types of air purifiers on the market today:

HEPA technology: High Efficiency Particulate Air or HEPA has replaced many standard air purifiers on the market. It’s designed to trap particles bigger than 0.3 microns 99.97% of the times. Based on what the human eye can see, which is 10 microns, HEPA technology is surprisingly accurate and qualified.

It filters out bacteria, viruses, and other types of microbes that are unknowingly floating in your indoor environment. That said, the best part about using HEPA technology is that it doesn’t emit any volatile compounds or unnatural byproducts. In simple words, HEPA technology strives to create a positive and sanitary environment. (3)

About the science behind this technology, HEPA technology uses fiber filters that have been repeatedly folded to create a maze of fiber strings. This ensures better airflow and air filtration toward the end. Once the HEPA filter is full, that means it’s filled with dust, the air will stop filtering immediately. This means HEPA filters need to be replaced every 2 to 4 years, based on usage.

The effectiveness of HEPA technology goes above and beyond for preventing heart diseases caused by air pollution. A study concluded that it reduces the total amount of airborne particles which improves blood vessel health and other blood biomarkers within the body. (4)

Activated carbon technology: As the name suggests, activated carbon technology makes complete use of carbon filters that have high absorbent capabilities. This is a very effective method of air purifying, a kind that has been used since early 1900s. Carbon filters (typically found in an air purifier for smoke) are good for filtering chemical emissions, cigarette smoke, and other harmful odors.

And contrary to popular beliefs, carbon filters do not push back the captured air, hence preventing any chances of recontamination. People who have lots of carpeting and upholstery furniture opt for activated carbon technology as it absorbs formaldehyde which is found in such heavy materials.

Simply put, activated carbon technology is a good solution for getting rid of dust, pollen, and other irritants for pets, children, and allergies.

The downside to activated carbon technology is that they’re not as efficient as HEPA technology. They don’t aggressively purify air from allergens and airborne compounds. (5,6,7)

UV technology: Air purifiers that use UV technology aren’t as effective as HEPA or activated carbon technology. But they do well to get rid of bacteria and viruses from the air. Based on how much light enters your room, the intensity of UV technology increases.

There are many downsides to using UV technology air purifiers. So you’re best using HEPA or activated carbon technology as the final air purification system for your home. (8)

3. Do You Need A Full Home Or Portable Air Purifier?

If you’ve come across full home air purifier systems, they’re more expensive than stand-alone, portable air purifiers. But searching for a complete home solution, on first glance, may be the perfect solution for people who want to keep their entire home clean and healthy.

Here’s what you need to know about both types of air purifying systems.

Whole house air purifying system

There are 3 main types of whole house air purifier systems:

  1. Filter-based units: These are installed directly into your home’s furnace system to control the amount of air intake.

  2. Duct-based units: These are installed directly into the air duct pathway.

  3. Stand-alone units: These can be directly installed in tight corners of the house such as the closet, the attic, etc. Installing stand-alone air purifying units with an exhaust is the most effective way to clean polluted air for your home.

Based on what I found, filter-based units are more expensive to purchase than duct-based units. They require better maintenance and operating cost than any other type of whole house air purifying system. (9,10)

The disadvantages of using whole house air purifiers can be:

  1. They’re expensive to purchase as well as maintain.

  2. The energy efficiency is inconsistent as it requires all day and night air filtration.

  3. They won’t fit in all types of houses and house structures.

Portable air purifying system

For most of you, whole house air purifiers may not be a practical buy for both energy efficiency and durability. On the other hand, buying a portable air purifier, the kind we’ve discussed at length above, functions primarily to protect the room it’s kept in.

It offers more flexibility options, is energy efficient, and comes with a comparatively low operating cost than whole house air purifying systems. You can keep the air purifier on when you’re in the room and shut it off when you’re out. It’s that simple to use and maintain. Plus, using expert air filtration technology, portable air purifiers offer excellent air cleaning and efficiency. (11)

You can take them from room to room. And you can buy the perfect size that fits your home. Another benefit of using portable air purifiers is that you can buy specific types based on your medical conditions (if you have allergies or other respiratory problems). The wide range of features present in portable air purifiers prove how efficient and effective it can be. (12)

These features include:

  • Multiple fan speeds

  • Filter changing capabilities

  • Remote control features

  • Digital control

  • Caster wheels for better portability

  • Air quality sensors

  • Filter change indicators

If you’re willing to choose performance over capacity, buying a portable air purifier is the right choice.

4. Choosing The Correct Size

It’s important to measure the room you want the air purifier in before finding the right purifier size. You can calculate by taking the square footage of the room into consideration. By measuring both the total length and width (in feet) of the room and multiplying both numbers together, that is length x width, can you determine the total square footage of any room.

You can keep the total number in mind when finding the right air purifier size. It helps when you look at the product’s specifications under manufacturer details when choosing an air purifier.

Another important factor to consider when looking at the size of any air purifier is change per hour, ACH, rate. This determines how fast can the air purifier can filter the total volume of air, based on the room size, per hour. So for people struggling with allergies or asthma, this information might help.

Based on recent reports, a standard air purifier can filter the air in any given room 4 times per hour. The ideal rate of 4 filter cycles per hour can remove all kinds of irritants, bacteria, chemical compounds, and viruses effectively. (13,14)

Based on the size of your room, that is the square footage, finding an air purifier that filters and purifies the air of even microscopic allergens that might trigger a severe allergic response is essential. Not to mention, it stimulates proper breathing which is the number one priority for asthma patients.

When choosing an air purifier, labels with 4 ACH rate is the recommended value for most rooms. To be able to make the most of such an air purifier, evaluating the Cubic Feet of air processed per Minute (CFM) is also good alternative. This measures how fast the air purifier would reach the square footage of any room’s air per hour.

The last important step is to decide where to place the air purifier. If you want a portable air purifier for many rooms, it’s important to calculate the average square footage of each room. That way you can buy an air purifier that comes with caster wheels and handles for better transportability.

5. Which HEPA Filter Do You Want?

If you want a cleaner environment indoors, opting for a HEPA filtration system for an air purifier is a good way to go. As mentioned previously, HEPA filter removes 99.97% of all particles that are below 0.3 microns. This has its own health benefits as it filters even the tiniest impurities from the air.

Microbes, bacteria, viruses, and other volatile compounds enter your room in such large amounts. And most of such microbes are unable to view detect with the naked eye. To find HEPA purifiers, look for the “true HEPA” or “absolute HEPA” labels, as they’re strictly regulated by the government. But other labels such as “HEPA-like” and “HEPA-type” aren’t true HEPA filter labels to look forward to. (15)

HEPA purifiers come with filters that need to be replaced every year. They come very close to the total price of the purifier itself, but considering how efficient and meticulous the filtration system is. Trapping many dust particles and irritants that are 0.3 microns in diameters is its most efficient quality.

When compared to HEPA purifiers, others don’t come close to such accurate performance. Why? Because the tiny particles that HEPA filters take care of are often passed down in the filtration process untouched. This is because of the tiny size of the dust particles and bacteria.

For that reason, HEPA filters come in certain types or letters from A through E. This determines how well the HEPA filter captures dust particles and other microbes from the air. (16)

Starting from type A, it’s the least efficient and precise air filtrating strength. But for general air purifying, type A HEPA filters match up to their stellar reputation on the market.

Type E are precisely the opposite of type A as they’re most commonly used for getting rid of harmful chemical and biological particles from the air. Only military grade air purifiers use type E for its rugged performance.

6. What’s The Noise Level?

You must have heard someone complain about a noisy air purifier at least once in your life. It’s not surprising to come across a silent air purifier, but that doesn’t mean it’s impossible. It’s important to take the noise level into account when choosing the right air purifier for your home. Based on the amount of noise the air purifier produces can you decide which room to put it in.

That said, what do you need to know about noise rating of an air purifier?

The kind of sound an air purifier produces is not mere sound, but it’s the air pressure waves that originate from the vibrating air purifier fan inside the appliance. This noise is oftentimes overlooked, but sometimes the noise increases in intensity causing an unpleasant and screeching sound.

To be able to measure the noise level of an air purifier, you have to look at the decibels or dB level of one. Even the quietest air purifier comes with a dB level so knowing it is critical to the air purifier buying process. The quiet sound noise levels for an air purifier is 15 to 36 dB, based on one report. (16)

Meanwhile, anything between 50 to 90 dB ranges from the noise level of a refrigerator to that of a lawn mower. According to one study, noise levels above 60 dB are considered too loud for humans to live with. (17)

All air purifiers come with a concise decibels rating for consumers. This level with give you a point in place when you’re making a final decision, especially when you’re buying an air purifier for your bedroom. A place where only the sound of traffic or birds chirping is acceptable!

On an ending note, finding a universal dB level for an air purifier is not enough. Like most features, this too is a subjective factor that depends completely on each individual. You might be comfortable with a 60 dB level while others may find it unpleasant and trying.

Also, where you position your air purifier also affects the noise level.

7. What Is The CADR Ratings Of An Air Purifier?

The CADR or Clean Air Delivery Rate is a concise indicator the defines the total volume of air filtered. If there’s a great amount of dust particles, tobacco, pollen, and other microbes in the air, the higher the CADR of an air purifier.

If you’re a first-timer, understanding certain labels and abbreviations of air purifiers can be confusing. That’s why narrowing down every single feature associated with air purifiers helps you get across your decision easily. If you’re home with dust, pollen, tobacco, and other mild irritants, it’s imperative the air purifier you buy is capable of handling the task at hand.

But knowing the CADR ratings of an air purifier is not the only way to determine its worth on the market. An air purifier with a higher CADR rating is effective, but that can also mean its effectiveness may decrease with time. Hence, choosing an air purifier based on its CADR is one of the important steps to take.

Along with the CADR rating of an air purifier, you will find area measurements for the purifier. This is a great way to determine how effective and powerful the air purifier is when placed in smaller rooms. Buying an air purifier with a lower CADR can be able to sustain for a longer time than a higher CADR purifier. So looking at all factors, including durability and filter replacement features, is important when considering the CADR rating of any air purifier. (18,19)

The certain disadvantages or limitations of CADR ratings is that they don’t measure gas or tiny particle filtration. So you won’t be able to determine how accurately the air purifier filters a specific volume of tiny dust particles from the air with the CADR ratings. Other volatile compounds including air pollutants and odors are also untouched by CADR ratings.

The Final Verdict

Air purifiers do what they do well - that is filter all sorts of pollutants, bacteria, and viruses from the air. While some lower-grade air purifiers do emit volatile organic compounds in the process, finding the right kind of air purifier that’s healthy and 100% efficient requires effort. That’s when this guide comes in handy.

You can make the most of your investment when you know which features to look for and factors to consider. It’s not an easy task to buy such an expensive and long-lasting appliance. Something that’s tied to improving overall air quality and fighting off allergies and other respiratory problems.

Using HEPA filters, rather than activated carbon filters, can have its own advantages. Most of which I’ve already discussed in at length. That said, it’s important to remember that using carbon filters for only 6 months is considered good for health and indoor air quality. So betting on activated carbon filters because they’re less expensive than HEPA is not a bad thing to do.

You can refer back to the maintenance factor of this guide to make the most of cleaning and maintaining your air purifier for a longer shelf life.

One last thing I’d like to talk about is customer service. Finding a good air purifier means placing your trust in a brand that appreciates your needs. And how else would you offer your feedback to a brand when it’s not appreciative and open to your criticism as well as compliments? That said, finding great customer service when it’s easily accessible is a major plus point for many consumers. (21)

You also want to choose a product with good warranty and performance guarantee. For a standard air purifier, the minimum product warranty should be one year. So you do not overspend on an ineffective air purifier and have to return the item immediately afterwards; causing more chaos and inconvenience on your end.

If you still have questions about the effectiveness of the air purifier you wish to buy, contacting the manufacturer for more details is a good way to proceed. You can also get access to the best air purifying specialists close to your local appliance store or contact one online for more information regarding air purifiers.

I’ve covered all basic and technical details of choosing an air purifier. There are many positive experimental results that own up to the effectiveness and efficiency of air purifiers. (22)

So buying one right away for its health benefits is the right thing to do!