Is My Air Purifier Big Enough For The Room?

Improving your air quality decreases your risk for a lot of serious health issues and can even lengthen your life expectancy. But, if your purifier isn’t powerful enough for the room you’re using it in, it won’t properly clean the air, leaving you vulnerable to pollutants.

So, how can you tell if your purifier is the right size? Let’s find out… 

Where is the purifier located?

Are you trying to clean the air in a bathroom? Bedroom? Kitchen? The entire house? While some rooms (such as kitchens) tend to have more pollutants than others, the amount of pollutants shouldn’t matter much to a good purifier. What does matter is the size of the space. It’s important to take measurements of the length, width, and height of the room you want to purify.

What’s the CADR of your purifier?

CADR stands for Clean Air Delivery Rate. It’s recognized by both the U.S. Environmental Protection Agency (EPA) and the American Lung Association.

CADR indicates how much air is filtered in an hour for three particular pollutants in Cubic Feet Per Minute (CFM). 

Although the particular pollutants are labeled as smoke, dust, and pollen, that’s only a general classification. Generally, dust represents the very smallest particles while pollen represents the larger ones like pet dander, dust mites, and larger particles of dust.

The higher the CADR number, the faster the air purifier filters the air.

Generally, the CADR of your air purifier should be equal to at least two-thirds of the room’s area.

So, for example, a room that is 15 feet by 10 feet has an area of 150 square feet. ⅔ of 150 is 100, so an air cleaner for that room should have a smoke CADR of at least 100.

To get an even more accurate number, include the ceiling height in your measurements by using the 3 x rule of thumb. 

For instance… consider you were looking to find the minimum CADR for that same 15ft x 10ft room, but now you are also factoring in the ceiling height of 8 feet. First, you would determine the volume of the room (15ft x 10ft x 8ft = 1,200 cubic feet). Using the 3x rule of thumb, you would then multiply the volume of the room by 3 (1,200 cubic feet x 3= 3,600 cubic feet per hour). To translate cubic feet per hour, divide by 60 (3,600cfph/60 =60 cfpm). So, the minimum CADR for a given pollutant in that room would be 60.

Since CADR is only meant to be a guideline, ceiling heights are not generally used unless you have a particularly high ceiling.

If you don’t want to do the math yourself, there are online calculators available to help determine the minimum CADR you’d need for each particular room.

What pollutants do you want to filter out?

Do you have allergies? Chemical sensitivities? Are you immune-compromised? 

While pollutants are dangerous to everyone, the more health concerns you and your family members have, the more important it is to get the right size purifier. 

Those with allergies or compromised immune systems should not only make sure that their purifier is big enough, but also that it uses a combination of True HEPA filters and activated carbon filters. The HEPA filter will remove harmful particles from the air, while the activated carbon filter will get rid of Volatile Organic Compounds (VOCs). 

Regardless of your health status, it is important to make sure that your purifier is powerful and effective enough to remove fine particulate matter. 

Fine Particulate matter, or PM2.5 are a mixture of solid particles and liquid droplets in the air that are smaller than 2.5 micrometers in diameter… meaning that they are about 30 times smaller than a human hair. 

PM2.5 are generated through everyday activity such as cooking and cleaning. They can also seep into your home through windows, doors, and tiny cracks. 

Because PM2.5 are so small, they are easily inhaled and are able to penetrate deep into your respiratory system causing a whole range of health problems.

Short-term issues from PM exposure include eye, nose, and throat irritation, coughing, sneezing, and shortness of breath. Long-term exposure to PM2.5 can cause permanent respiratory problems such as asthma, chronic bronchitis, and heart disease. PM2.5 particles also increase the likelihood of premature birth and infant mortality.

One recent study called PM 2.5 “the largest environmental risk factor worldwide,” responsible for many more deaths than alcohol use, physical inactivity or high sodium intake. In fact, 4.2 million people die every year from breathing in large amounts of fine and ultrafine particulate matter. 

So, shouldn’t you just use the biggest purifier possible to be safe?

No! A purifier that is too big will be a waste of money and energy. Finding the right size purifier is the most economical and effective option.

For rooms under 700 square feet, we recommend the aair lite. The aair lite uses HEPA H13 Filter to Filter 99.95% of ultra-fine particles at 0.1 microns, ensuring that pollutants like pollen, dust, smoke particles, pet dander, and more will be removed from your home in minutes. It’s small and easy to transport, so you can move it from room to room if necessary. 

For rooms up to 1500 sq ft in size, consider the aair 3-in-1 Pro. It uses a HEPA 13 filter embedded with 2 lbs of activated carbon to filter out both VOCs and 99.95% of ultra-fine particles at 0.1 microns. 

Check out our site to find the right size purifier for your home. 

What Are The Biggest Health Risks From Air Pollution?
For decades, scientists have been warning us about the serious...
Which Kind Of Purifier Is Best For People With Asthma?
Over 25 million Americans suffer from asthma. While there is...
Sleep Habits Across America: A Survey
Beauty rest, catching some Z’s, 40 winks, or shut-eye—whatever you...
aeris air purifier in office setting
Affirm + aeris by iRobot

As low as 0% APR Financing with Affirm

As an example, a $1,000 purchase might cost $333.34/mo over 3 months at 0% APR.
Quick and easy
Enter a few pieces of information for a real-time decision
No hidden fees
Know up front exactly what you'll owe, with no hidden costs and no surprises.
Just select Affirm at checkout

Your rate will be 0% APR or 10–30% APR based on credit, and is subject to an eligibility check. For example, a $1000 purchase might cost $90.36/mo over 12 months at 15% APR.  Payment options through Affirm are provided by these lending partners: Options depend on your purchase amount, and a down payment may be required.


How Tax is calculated

The amount of tax charged on your order depends on many factors including the following:


  • The identity of the seller
  • The type of item or service purchased
  • The time and location of fulfillment


The shipment or delivery address of your order
These factors can change between the time you place an order and when your shipment is complete. As a result, the tax calculated on your order may change. We display an “Estimated Tax” to be collected at Check Out when confirming an order. The amounts displayed as estimated tax may then be updated later when your order is finalized and completed.


The tax rate applied to your order will be the combined state and local rates of the address where your order is delivered to or fulfilled from. For example, if you live in a state that does not impose a sales tax, you may still see tax calculated on your order if shipped to another state. Moreover, the tax rates applied to your order may also be different for a variety of reasons, such as a shipment to a residential home versus a business address. Also, the total selling price of an item will generally include item-level shipping and handling charges, item level discounts, and gift wrapping charges. If applied at an order level, these charges, may be allocated to the individual items in an order.


If you are ordering from aeris and shipping to a country outside of the US, you may be charged the applicable country tax rate.

Contact customer support: