Air Purifiers: How Many Do You Need for Your Home’s Size?

In general, having an air purifier in the areas where you spend most of your time is a good idea. This might indicate the necessity for at least three air purifiers for your house, one for larger spaces such as the bedroom, kitchen, and living area.

You would need an air purifier when your house smells like paint thinner or exhaust to eliminate the stiff smell.


How Can You Tell Whether You Need More Air Purifiers?

You may be surprised if you believe a single portable air purifier is enough for your household. You may require more than one air purifier to attain the best results.

There are several things to consider and some calculations to calculate how many air purifiers your home will require.

Estimating The Volume Of Indoor Air

The quantity of indoor air may be calculated using a simple calculation. It works like this:

Volume (interior air) = Indoor area (in square feet) x ceiling height (in ft)

For instance, your indoor air estimate looks like this if your home is 1,000 square feet in size and has 8-foot ceilings:

1,000 square feet x 8 feet = 8,000 cubic feet

It will take around four cleaning cycles to purify 8,000 cubic feet of air sufficiently. This is often known as 4 ACH (Air Changes Per Hour). This implies you must cleanse 4 × 8,000 feet of air every hour.

The Volume Of A Typical Air Purifier

Once again, your chosen device will determine your air purifier’s capacity. However, the typical airflow of most air purifiers is 200 CFM (cubic feet per minute).

This indicates the machine has a 200 cubic foot air cleaning capacity each minute.

Air Purifiers In Use Overall

As a general guideline, you need an air purifier that can move roughly 100 CFM for every 250 square feet of area. You’ll need a measuring tape and a helping hand to determine the floor space of your room.

Your room’s length and breadth should be measured in feet. The size is then determined by multiplying the two values.

Once you’ve determined the square footage, consider the following:

The number of air purifiers = the amount of air to be purified (in ft/h) / the air purifier airflow (in ft/h).

Three high-quality units clean around 24,000 feet of air, whereas one air purifier cleans 12,000 feet.

If your facility is 32,000 square feet, you’ll require two and a half air purifiers. Because you can’t buy half a purifier, we recommend getting three rather than settling for two and getting subpar results.

Link Between Home Size And Air Purifier

A smart move would be to purchase many air filters for various spaces. The size and kind of air purifier you’ll need may be decided after the dimensions of each room that gets the most traffic, and the projected pollution levels are known. Here’s an illustration:

Area of CoverageAir Changes Per Hour (ACH)Required number of air purifiers

Just cut the number of air purifiers in half if your space only needs two air changes each hour. However, it is advised that you constantly aim for 4 ACH for better air quality.

Larger areas, like the dining and living room, may need 2 or 3 purifiers in more extensive settings, like 3,200 square feet. Multiple air purifiers may also be required in rooms with smoking.

Tips For Getting Better Results

If you desire the highest performance from your air purifier, stick to these tips to choose the most excellent model and guarantee that it performs at its peak.

  • Subtract 50 square feet from the manufacturer’s recommended square footage to ensure that it will fit precisely in your space (to compensate for any differences between ideal test conditions and real-life conditions).
  • Use the formula CADR x 1.55 to get the room size in which an air purifier device can purify.
  • Purchase an air purifier with at least a 2x ACH rating.
How Long Should You Run An Air Purifier

Where Should You Install Your Air Purifier?

The location of the air purifier affects the performance of the cleaner significantly. Even though air purifiers are excellent at bringing in air, they perform at their peak when they have strong airflow and a lot of air access.

The purifiers can clean the air more quickly when more air is available. Most of the air may enter and be cleansed by your purifier if placed close to windows or entrances.

Another reason to install air purifiers at entrance points is that flowing air has enough force to remove dust, mold, and other particles and disperse them throughout your home.

A purifier at entrance points cleans your indoor air since you can eliminate pollutants before degrading the air quality in the remainder of your home.

For the air purifier to effectively purify the air in the whole room, it is usually a good idea to give it at least a foot of clearance on both sides, the front, and the rear.

This entails keeping the space as clear of obstacles as possible and avoiding positioning the purifier in corners.

Consideration should also be given to vertical airflow. An air purifier’s capacity to clean the air will be increased if it is placed 3 to 5 feet from the ground to catch both lateral and vertical airflow.

Larger units can occasionally be fixed on the wall, while smaller ones can be set on a desk or table.

What To Look For When Purchasing An Air Purifier

It’s essential to look into details when purchasing an air purifier, like its ACH ratings and HEPA filtration. Consider the following variables to get the most out of your air purifier while avoiding specific harmful effects:

Size Suitability

Air purifiers of various sizes are designed to purify the air in specific spaces. Confirm the suitable room size with customer service representatives from multiple companies.

Reduce your energy costs by buying a model made for a bigger space. As a result, even in lesser settings, the air purifier remains effective.

Noise Level

Most air cleaners with HEPA filters emit noise between 35 and 70 dB. Depending on your operational parameters, the noise level will vary. Choose air purifiers that work even at low noise levels to prevent sleep interruptions caused by noise.


You must consider how long you should run your air purifier before buying one. You might need to run the air purifier all day long, depending on the size of your house. So make sure the air purifier is durable enough to run for the whole day.

Certification For Asthma And Allergies

With Allergy Standards Limited’s (ASL) help, the Asthma and Allergy Foundation of America created a certification program.

Before certifying items, they tested them to verify that the air purifiers eliminated the most dangerous particles.

Air purifiers that pass the program’s tests get the “asthma & allergy friendly” label. The accreditation guarantees a high-quality product with outstanding air filtration capabilities, making it ideal for allergy sufferers.

ACH (Air Change Per Hour) Rating

The amount of times every hour that the total amount of air in the room is filtered is indicated by the ACH rating. A higher ACH rating indicates more efficiency.

Choose air filters with, at minimum, a 4x or 5x ACH rating if you are susceptible to allergies or asthma.

In this manner, you ensure the interior air is filtered more quickly.

Cost Of Maintenance

Many people might think that air purifiers are a waste of money. Air purifiers are typically priced at $150. Depending on the brand, maximum room size, and filters, others may be purchased for a more excellent or cheaper price.

Before purchasing an air purifier, consider the expense of upkeep, and decide your budget.

The maintenance cost is determined by how frequently you must change your filter. You should also include the cost of your HEPA filter in your energy statement.

Some air purifiers, such as ones with UV lamps, include washable filters, although they require more watts. This may increase your power bill. 

Energy-efficient HEPA air purifiers should have their filters cleaned every three months for the best results. Filter replacement typically costs $100 per year. You can spend more money on filter replacement if you get a purifier with many filters.

For instance, replacing the HEPA and activated carbon filters in your air purifier every three to four months may cost you more than $100 annually.

Frequently Asked Questions

Q. How long does an air purifier take to clear space?

When operated correctly, most high-quality air purifiers will cycle the air in a room for 15 to 20 minutes.

The atmosphere in a room may require multiple cycles to be thoroughly cleaned. Still, in general, an improvement should be seen in 2 to 3 hours.

Q. Can air cleaners operate continuously?

Yes, most manufacturers believe that a home’s air purifier runs continuously. The air in an area can already be constantly cleaned using air purifiers. An air purifier serves little benefit if it is manually turned off and only used for a few hours each day.

Q. How much power do air purifiers consume?

An air purifier of medium size typically uses 50 watts of energy. The air purifier in the device consumes the majority of the electricity.

On average, a unit that operates for 12 hours will cost you roughly $2.15 each month. This assumes that the unit runs at full speed and that your power tariff is 12 cents per kWh.

Q. Can a room handle a large air purifier?

The quick response is both yes and no! In general, bigger air purifiers are more effective in cleaning the air. You might get a sizable air purifier as a result for your house.

However, it is unnecessary to purchase a large tank air purifier to serve a tiny space like a bedroom that is just 100 square feet if it is only a small room. A huge air purifier could be too big for space in this case.

Q. How Many Air Purifiers Should I Have in My Home?

You may need at least three air purifiers in your home, one for each place you spend the most time, such as the bedroom, kitchen, and living room.