Are you wondering, “What size air purifier do I need?”

If so, this guide is for you.

In this post, we’ll show you how to determine the proper size you need for an air purifier.

This is an essential step when going through the process of deciding how to choose an air purifier that’s right for your home.

Getting the right size air purifier is important because it ensures that the unit will work most effectively inside a room.

The worst thing you can do is buy an underpowered air purifier and it not do a very good job at cleaning the air around you. While you may think you’re breathing healthy air with it running, you most likely are not.

This guide will ensure that this situation doesn’t happen to you because you’ll walk away knowing how to get the correct air purifier room size.

And to make things easier for you, we’ve put together another article with the top 10 air purifiers here so you can make a good selection.

>> See all of Amazon's Best Selling Air Purifiers <<

Air Purifier Room Size Guide

Air purifier room size comparison

Asking the question, “How big of an air purifier do I need?” is very common. So lets first start with the typical sizes for air cleaners.

Air purifiers come in four sizes, with each one being good for a specific room size that’s measured in total square feet.

  • Small air purifier: Good for personal spaces and rooms up to 200 square feet. 
  • Medium air purifier: Good for rooms between 200 and 400 square feet. 
  • Large air purifier: Good for rooms between 400 and 1,500 square feet. 
  • Whole-House air purifier: Good for purifying every room in the house.

How to Choose the Right Size for an Air Purifier

To choose the right size air purifier, you need to measure the square footage of the room you want to purify. Then you want to pick an air purifier that can meet or exceed that specification. Choosing the right size for air purifiers is essential for the cleanest air.

Step 1: Determine Where You Want to Place the Air Purifier

The most important factor when determining what size air purifier do I need is to first decide where you want to place it.

Are you looking to purify the air within a single room, multiple rooms, or an entire house?

The answer to that question will help narrow down the optimal product choice for your application and make it much easier to compare air purifiers.

Step 2: Measure the Square Footage

How to Choose the Right Size for an Air Purifier

After making a room decision, the next step is to figure out what the square footage is for the space you want to purify.

If it is a single room, this step is quite easy.

All you have to do is use a measuring tape to take measurements of the two perpendicular walls.

This will allow you to determine the square footage for the room.

For example, a 10′ x 12′ room = 120 sq. ft.

If you want an air purifier that will clean the air for multiple connected rooms, then just measure the length and width of each room separately and add up the totals.

For example, if we have two adjoining rooms that are 120 square feet and 80 square feet, then the total square footage would be 120 + 80 = 200 sq. ft.

If you’re trying to size an air purifier for an entire house, the easiest method would be to look at the paperwork from when you bought the home.

That house plan should include the total square footage for your house.

If you can’t find this documentation easily, a simple method is to go outside and measure the length and width of your outside walls.

Then multiply that number by the number of levels your home has.

For example, if the outside square footage equals 1,200 square feet and you have a two-level home, this would be 1,200 x 2 = 2,400 sq. ft.

Step 3: Match the Square Feet Rating on the Air Purifier to Your Room

Air purifiers come in all shapes and sizes and carry a maximum square footage rating on their specifications list.

Therefore, all air purifiers are effective for certain size rooms.

The best air purifier size is one that meets or slightly exceeds the square footage of the room you’re using it in. So look for the closest match possible between the total square feet of the room and the coverage of the air cleaner. Doing this will allow you to enjoy the full benefits of air purifiers.

Can an Air Purifier Be Too Big for a Room?

Technically, an air purifier can be too big for a room. But it will still clean the air efficiently. The biggest downside here is that you’ll be paying too much for the unit and have more costly filter changes.

If you’re looking to buy an air purifier just to purify a small bedroom or living room, then it doesn’t make sense for you to buy a device that can clean a maximum of 3,500 square feet.

Not only will this air purifier be too powerful for the room, but it will also cost you more money to buy, use more electricity, and require more expensive filters.

Therefore, it makes better sense to get an air purifier for a room size that is properly sized for your application.

For example, if your room measures 150 square feet, then get an air purifier that indicates a square footage rating that is equal to or just above this number.

An air purifier with a 200 or 250 square feet rating would be just as efficient as a unit that measures 150 square feet exactly for that size space.

For large spaces, we suggest that you visit our our large room air purifier reviews page to see what the top models are available.

Can an Air Purifier Be Too Small for a Room?

Yes, an air purifier can be too small for a room.

What you don’t want to do is buy an air purifier that doesn’t meet a room’s total square footage size.

Buying a device in order to save money that can only purify a room up to 80 square feet would be a waste of your investment because it won’t be able to purify that large of a room.

If you’re trying to buy a product to purify your entire house, yet you can’t find a product that has a high enough square feet rating such as 5,000 square feet., then you’ll need to make some compromises.

Instead of trying to purify your house with one device, it makes more sense to break your home up into small square footage sections and find a device that will work well for this size.

For example, if each level measures 1,500 square feet in a 3 level home, consider getting an air purifier that is sized to purify 1,500 square feet.

Then buy three of these devices and place one on each level of your home.

That way you can ensure that you are optimizing the efficiency of each device.

If you live in an apartment, things get a little bit easier and more affordable because you don’t have to purify as large of space.

Many apartments fall into a standard square footage size so finding a proper air purifier match is simple.

Check out our guide on the best air purifier for apartments here to find out what’s available.

How Many Air Purifiers Do I Need?

How many total air purifiers do you need in your home?

Generally speaking, it’s best to have at least one air purifier in each of the rooms where you spend the most time.

For example, if you spending a lot of time in the living room, a home office, and a bedroom, then having three air purifiers would be the optimal choice.

If you only hang out in the living room and bedroom, then it’s good to have two air purifiers.

It’s best to let an air purifier run all day and night for the most effective use of the machine. That’s why it’s recommended to have one air purifier per room you frequent most.

However, many air purifiers are portable. So you can take one of those units around the house with you if you want.

But just remember, the longer an air purifier has time to filter the air inside one particular room, the cleaner that air becomes. 

Moving an air purifier, regardless of size, from one room to another without enough time to operate, won’t result in clean air to breathe.

If you’re concerned about the air quality at your workplace and work in an office, then you may want to consider one of the models our best air purifier for office list. Having a dedicated office air purifier can help keep the air around you at work clean and fresh to breathe.

A final option would be to get a whole home air purifier. These units attach to the HVAC system in your house and filter the air that’s being heated and cooled. Check out our best whole house air purifier for furnace list to learn more about how these units work if you want total home air purification.

Can You Use Multiple Air Purifiers in One Room?

Yes, you can use multiple air purifiers in one room.

Several air purifiers can work together to clean the air in a room.

For example, if you have a large room, such as 1,200 square feet, and have two air purifiers that can cover up to 600 square feet, then you can use them both in the same room to clean the air in that room.

You could also use three smaller air purifiers that cover up to 400 square feet each for a 1,200 square feet room.

Example Room Size for Air Purifiers

Below are some example air purifiers with their room sizes (i.e. total square footage).

You can use this list to find a quick recommendation for a good air purifier room size.

Also, check out our complete list and reviews of the top 10 air purifiers here.

  • Levoit Core 300: air purifier for 200 square feet
  • Dyson Pure Cool Link: air purifier for 300 square feet
  • Honeywell HPA300: air purifier for 400 square feet
  • Airocide: air purifier for 500 square feet
  • Molekule Air: air purifier for 600 square feet
  • Rabbit Air MinusA2: air purifier for 700 square feet
  • IQAir HealthPro Plus: air purifier for 1,000 square feet
  • Alen BreatheSmart: air purifier for 1,200 square feet
  • AIRMEGA 400: air purifier for 1,500 square feet

What Size Air Purifier Do I Need Summary

What size air purifier do I need

We hope you enjoyed this guide on how to select the right size air purifier for your home.

As you discovered, the answer to the question, “What size air purifier do I need?” is dependent on the total square footage of the room that you want to purify.

And when you pick a unit that meets or exceeds that specification, then you’ll get the cleanest air at the most efficient rate.

So be sure to measure the room size before shopping or an air purifier. That way, you’ll get the most effective unit for your home.

Avatar for David Morrison

About David Morrison

David is an Air Quality & Comfort Technician. He has expert knowledge on the technology and design of air purification, air conditioning, and heating systems. His main role is to write content that helps people get the most value out of their air purifiers, air conditioners, and heating units. (See Full Bio)