How Many Air Purifiers Do I Need? (And What Size to Get)

If you’ve never had an air purifier before, the first question that probably comes to mind is “How many air purifiers do I need?”

The second question most likely question is “What size air purifier do I need?”

It’s completely natural for you to wonder if you only need one air purifier for the entire house or a separate device for each room. With so many different options available, and a wide ranges of prices, it can be confusing to know exactly to do.

In this post, we’ll explain what you need to know in order to figure how many air purifiers you need as well as what size to get to keep your indoor air healthy. 

Hint: Plan for an Air Purifier in Each Room

When it comes to getting the most effective coverage with an air purifier, you really want to use a dedicated unit in each room.

While that may seem like an expensive endeavor, the truth is that most people don’t purchase an air purifier for every single room of the house.

The most cost-effective choice is to limit the use of an air purifier to only the rooms you spend the most time in such as the living room, a bedroom, or home office. 

At a minimum, you should place an air purifier in your living room if you spend the majority of the time there. Otherwise, put one in your bedroom since you’re likely spending 6-8 hours stretches of time in this location every night. The goal is to have the cleanest air possible for the longest stretches of time indoors.

If you can afford to purchase an air purifier for multiple rooms, by all means, this is the best option for the most effective air quality improvement at home. And it doesn’t have to be expensive either. Take a look at our guide on the best cheap air purifier options to see what’s available.

Now, the next question your probably having is what size air purifier should you get? We’ll answer that next.

What Size Air Purifier Do I Need?

In short, this depends on the size of the room you want to use the air purifier in.

Unless you spend an absorbent amount of money, most air purifiers are generally not powerful enough to keep up with multiple rooms. Plus, if two rooms are blocked off by a wall or small doorway, an air purifier won’t be able to filter air through these obstacles.

So, what size air purifier do you need for a particular size room? Read on to find out how to calculate the square footage of your room or rooms you want to improve air quality in. Then head over to our other post that explains what is the best cheap air purifier and important features to look for.

Note: You can find the square footage coverage listed on the air purifier’s box or online specifications chart.

How to Calculate a Room’s Square Footage

Figuring out the square footage for a single room is easier than it may sound. Just follow these simple steps:

  • Take a measuring tape and measure two perpendicular walls
  • Write down the length of each wall in feet
  • Multiply the two numbers together to get the total square footage of the room 

Here’s an example to help you get started:

  • A 15 feet long x 10 feet wide room = 150 square feet

Note: For odd lengths like 12′ 1/2″ or 10′ 3/4″, just round up to the next whole number to make your math easy. Rounding up won’t make much difference in the final total but it ensures you get a properly sized air purifier than if you rounded down.

Now, if you have two rooms that are connected by a wide doorway opening like a dining room and living room or through an open concept design like a kitchen and living room, then you’ll want to perform an extra step to get the right size air purifier to cover both of the rooms at the same time.

Measure the square footage of each room independently and then add those two totals together.

For example, if one room has 150 square feet and the other has 200 square feet then you’ll add those two numbers together to get 350 total square feet.

If you want to buy an air purifier that’s powerful enough for both of these rooms simultaneously then you’ll need one that can cover at least 350 square feet. 

Making Sure Your Home Has Coverage

If you don’t have a large budget, but you want to cover your entire home, it may be more cost-effective to purchase a cheaper air purifier because you can buy multiple ones and use them in different rooms. For more about how much does an air purifier cost, take a look at that post.

However, if you have larger rooms, you may have to pay more to get a more powerful air purifier.

If you’re on a budget and concerned with just having fresh air nearby, you could choose to buy a cheaper air purifier and place it on a table next to you. Cheap air purifiers have limited square footage coverage (under 100 sq. ft.) but if it’s near you then you can at least purify the space directly around you when you’re inside the room. Take a look at our post on small room air purifier options to see what you can get.

So, how many air purifiers do I need and what size air purifier should I get? Hopefully, you now know the full answer.