How Many Air Purifiers Do I need? (1 For Every Room?)

It's no secret that you need more than one air purifier for your home. But how many air purifiers exactly do I need for absolute clean air? Should I place an air purifier for every room or better breathability? Can I trust the manufacturer's specifications? Wonder no more as we will guide you through the whole process, especially if you are a first-time buyer. We will explain why you need more than one air purifier, evaluate the room size, and what type of air purifiers to go with. At the end of the post, you should have a clear idea of how many air purifiers work best in improving indoor air quality.


Before we begin, let me clarify that there is no definitive answer on the number of air purifiers you should own. Some people might be content with one, while others require more due to health and environmental conditions. Always start with one and after months of use, consider all facts before buying an additional air purifier. Refer to the below information as a general guideline for deciding what’s best for you and your family.

how many air purifiers do i need

How Many Air Purifiers Do I Need In My House?

Depending on the room size, you will need at least one air purifier to move around the house for room-to-room air-purifying or leave it at the place you spend the most time in. Ideally, you should have an air purifier in every room to tackle different airborne pollutants effectively. Due to the cost, most households would settle for 2 air purifiers running day and night for complete air cleaning. First, you will need a large air purifier to cover the living room and kitchen air cleaning space. Second, a tabletop/ small air purifier for the bedroom where you sleep most of your time. Depending on your air purifier CADR and purifying coverage, additional units might be required for room spaces not covered. For example, you may need an extra air purifier to rectify the deteriorating air quality in your basement or garage.

Not everyone has the same health condition and air quality tolerance level. One family member might have trouble with pet dander from domestic pets. At the same time, another person might suffer from MCS but have no issue with pets. It makes perfect sense to always have an air purifier by your side. Otherwise, save the hassle and get one in every room. Having more than one air purifier at home will ensure the indoor air is always clean and free from dust, dust mite, pollen, mold, pet dander, chemical smoke, bacteria, and viruses. You are less likely to fall sick from allergies with cleaner, healthy air.

For example, a plug-in air purifier focuses on neutralizing germs, bacteria, and viruses. In contrast, the main HEPA air purifier focuses on removing microscopic particles. An air purifier with an activated carbon filter will best suit kitchen or bathroom use to deal with stinky odors. Just keep in mind there is an additional electricity cost and the filter replacement cost to bear.

Single Or Multiple Air Purifiers?

You can never have too many air purifiers, as there are no perceived drawbacks other than the cost of ownership. The advantage of having multiple air purifiers in a home is having wider room sizes and efficiently targeting different types of airborne contaminants. As a comparison, the airflow circulation of a single air purifier would often be impeded by walls, doors, furniture, and cabinet before it can distribute clean air across the home. With multiple air purifiers, you can customize each device to target specific contaminants in a room. For instance:

  • VOCs air purifiers – dedicated air cleaning device that removes chemicals, smoke, VOCs, and Formaldehyde.
  • Bedroom air purifiers – Smaller, tabletop size for nightstand use with low noise operation.
  • Fan air purifiers – Stuffy, hot room like an attic that could do with some cooling and clean air.
  • Basement air purifiers – Specializes in removing mold, mildew, and other airborne microorganisms.
  • Kitchen air purifiers – Keep kitchen air fresh and prevent lingering smells from distributing around the house.
  • Baby air purifiers – Cater for those with a newborn or little one at home.
  • Pet air purifiers – Designed to trap pet dander, germs, and pet odors from your cat or dog.

Another surprising fact is multiple air purifiers can be more cost-effective than a single, whole-house air purifier. A mid-range residential air purifier would cost you around 100-300 dollars. In comparison, a whole-house air purifier can easily cost you between 2000 to 6000 dollars. A whole-house air purifier is also costlier to maintain as installation or major cleaning requires the service of HVAC specialists. Last but not least, if you opt for a whole-house air purifier, you will have minimal options to go with compared with console air purifiers.

Ultimately, if you are on a tight budget and can’t afford multiple air purifiers, go with a single, medical-grade HEPA air purifier with the portability for room-to-room purifying. Make sure the air purifier has adequate airflow capacity and focus on a room with the worse air quality or where you spend the most time in. Remember, having one air purifier is still better than none.

What Size Of Air Purifier Do I Need?

What Size Of Air Purifier Do I Need?

You should always purchase an air purifier that at least matches the room size you need to purify. For example, a 700 sq. ft. room space requires a large air purifier that has the suggested room size purifying coverage to support that. Alternatively, get two smaller air cleaners that each will cover a 350 sq. ft. of room space. With two smaller units, you can effortlessly move the compact air purifier for room-to-room air cleaning as long as it is lightweight and portable to do so. We recommend a model like Levoit Core that weighs under 10 lb with a built-in grabbing handle.

To choose the right size air purifier, you will need to measure the room’s square footage that needs cleaning. The easiest way is to get the master floor plan, and you will have the square footage of the rooms. If you don’t have that, get a measuring tape and measure the two perpendicular walls in feet. Multiply the width and length numbers, and you will have the room’s square footage. Rinse and repeat the steps to get the rest e.g. living room, kitchen, and dining room. Add those numbers together, and you will know what sizes of air purifiers are needed to cover your entire home.

To calculate the total volume of indoor air needed in cubic feet (ft³), use the following equation:

Volume of indoor air (ft³) = Indoor area (sq. ft.) x Ceiling height (ft)

For example, in a 500 square footage home with 8 ft of ceiling height, the total volume of indoor air will be: 500 sq. ft. x 8 ft = 4,000 ft³

manufacturers recommended room size box

To check on the air purifier’s performance, you can quickly identify through the official manufacturer’s recommended room size. The numbers shown are usually based on 2 air changes per hour (ACH). To get the recommended room size in 4 ACH, divide the suggested square footage by 2. ACH is the number of times an air purifier can filter the air hourly. If you are an asthmatic or hyperallergic person, you will need 4 air changes per hour or clean air every 15 minutes. To determine which model would suit you best, visit our curated best air purifier to prevent an asthma attack page.

Clean Air Delivery Rate (CADR) is another way to determine the air purifier capacity. Developed by the Association of Home Appliance Manufacturers (AHAM) to create an industry-standard measurement, CADR is a metric used to rate the hourly airflow performance of an air purifier. The volume of filtered air is measured in cubic feet per minute (cfm) with three separate tests conducted for dust, pollen, and smoke. Take note that not all air purifiers participate in AHAM certified, independent tests. For models that do, you will have a voluntary label called AHAM Verifide printed on the box verifying that the air purifier is independently tested, as below.

AHAM Verifide CADR Energy Label

As you can see, a true AHAM Verifide label should give you the CADR in cubic feet per minute (ft3/min) instead of cubic meters per hour (m3/h). Make sure you read the label carefully, as some manufacturers will mislead the buyers by jacking up their numbers.

Below is the table on how many air purifiers are needed in different room sizes based on an 8 feet ceiling height at 2 air changes per hour (clean air cycle every 30 minutes). If you increase the ACH to 4 (clean air every 15 minutes), you will need to double the total air purifiers inputted here.

Room Sizes
(Sq. Ft.)
Total Volume (ft³)
(8 FT Ceiling Height)
Number Of Air Purifiers
Needed (2 ACH)
Best Used In
36288231 small air purifierSmall bedroom, dry bathroom, breakfast nook, bedroom, utility room, foyer, porch.
49392321 small air purifier
64512411 small air purifier
81648521 small air purifier
100800651 small air purifier
121968781 small air purifier
1441,152931 small air purifier
1691,3521091 medium air purifierDining room, patio, guest room/ bedroom, dens, gazebo, walk-in wardrobe, small kitchen.
1961,5681261 medium air purifier
2251,8001451 medium air purifier
2562,0481651 medium air purifier
2892,3121861 medium air purifier
3242,5922091 large air purifierMaster bedroom, family room, lounge, basement, garage, office area, nusery home, kitchen.
3612,8882391 large air purifier
4003,2002651 large air purifier
4413,5282931 large air purifier or
2 medium air purifiers
4843,8723211 large air purifier or
2 medium air purifiers
5294,2323511 large air purifier or
2 medium air purifiers
5764,6083831 large air purifier or
2 medium air purifiers

The Different Types of Air Purifiers And Pollutants

The types of air cleaners will also determine if you need to place an air purifier in each room. Choose from a HEPA air purifier, deodorizer, UVGI cleaner, PCO Cleaner, Ionizer to Electrostatic precipitator. The best option would be a mechanical air purifier with a HEPA filter and a carbon filter. It is the safest and most effective, unlike other air cleaners focusing on a particular set of pollutants. For example, a carbon air purifier can only remove smoke particles and odors, while a UV sanitizer is only great against pathogens.

Do Air Purifiers Use a Lot of Electricity?

No, as most air purifiers have a low power consumption rate identical to other smaller home appliances. In fact, some air purifiers consume as little electricity as a light bulb. Even if you leave the air purifier running all day for months, you will not see any major spike in the electricity bill. Some states, like Hawaii, have higher electricity tiers that will snowball the cost quickly. Pick the right size air purifier based on your room size, and look for an Energy Star-certified unit for better energy management.

How To Choose The Right Size Air Purifier?

There are many different sizes of air purifiers in the market, but not all would suit your needs. Surrounding your house with many cheap air purifiers may not be the most cost-effective solution. The truth is, not everyone needs more than one air purifier. Sometimes having a powerful air purifier and placing it at the center of the room would be good enough. But before you blindly purchase multiple air purifiers without knowing what you are getting at, ask yourself the following questions:

  • How many rooms are in my house, and which space do I regularly occupy?
  • What is the total square footage needed for the air purifier to clean?
  • What type of airborne contaminants are you dealing with?
  • Does the air purifier have the correct type of filtration and airflow volume to tackle indoor pollutants?
  • Can I afford to own and maintain more than one air purifier?

How Long Does It Take For An Air Purifier To Clean A Room?

On average, an air purifier would take 30 minutes to 2 hours to clean the air in a room. Regardless of the cleaning time, we highly recommend leaving the air purifier cycle clean air all day to prevent dust from building up.

Can An Air Purifier Clean A Whole House?

It is possible with a whole-house air purifier, but not without limitations. There are far too many obstructions in a household e.g. furniture, wall, cabinet, and electronic appliances, that would impede the airflow circulation of an air purifier. We recommend complementing your whole-house air cleaning HVAC system with single or multiple air purifiers across your home for better air cleaning efficiency.

Final Thoughts

Single or multiple, the number of air purifiers in a home should not be the only factor in determining the overall air cleaning performance. You should also pay equal attention to the types (no Ozonator please), size, and filtration depth. Upkeeping is also an essential aspect of air purifier ownership. The outer pre-filter requires cleaning every 2-3 weeks to prevent clogging or damage. The disposable HEPA and carbon filter must be replaced when the filter change indicator light is up. Make sure the air purifier is working and leave it on all day, all night, to enjoy a constant flow of clean air. Last but not least, place the air purifier close to the pollutant sources or by the doorway while leaving 2-4 feet of breathing space for ventilation. You can learn more about the art of air purifier placement here.

Max Fernandez

A loving father and a dedicated reviewer for airfuji.com with more than 1000 air purifiers under his belt. Max Fernandez is also one of the million patients currently suffering from asthma. Feel free to nudge him if you have any questions.
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