Do You Need an Air Purifier in Every Room?

If you’re someone who wants to make sure the air you breathe at home is clean, you may be wondering if you need an air purifier in every room.

After all, most of us appreciate a clean home and someone – or something – that’s doing their share in keeping it that way. 

So you dust, clean, and vacuum, but do you need an air purifier in every room too?

The short and sweet answer is no. You don’t need an air purifier in every room—at least in most cases. 

Having said that, there are several factors to consider. For example, do you have a tiny air purifier that only covers the area of a typical-sized powder room?

Let’s dig deeper into why you may or may not need an air purifier in every room. 

But first, a little air purifier 101 is in order, as it will help you understand why you may or may not need multiple air purifiers.

Size Matters: Do You Need an Air Purifier in Every Room?

When asking yourself if you need an air purifier in every room, there are two very important factors you’d want to consider: the size of your air purifier and the size of your home.

The Size of your Air Purifier

How big is your air purifier, and how big is your home or the rooms in which you want to put a purifier?

This isn’t rocket science, so you should know that just like homes come in various sizes, air purifiers do too. 

You can find models that will cover the area of a small room to whole home air purifiers—but the latter are typically attached to your HVAC.

Regardless, every air purifier will have the coverage area listed on the packaging. 

If you’re buying something used, Google the model number, and you should be able to find out the coverage.


The Size of your Home

Next, the size and layout of your home.

Do you have a home with many small—or large—rooms, or is it more of an open concept with no actual rooms? 

Where do you spend the most time? Do you have pets, and where do they spend most of their time?

This should help you determine the priority rooms you’d want to put your purifier in.

Choosing the Right Size Means You Won’t Need an Air Purifier in Every Room

Choosing the right size, to begin with, means there’s a good chance you won’t have to question whether you need an air purifier for every room.

Since air purifiers are available in four basic sizes, it’s easy to narrow down the right size for you and your home.

  • Small purifiers are suitable for rooms and spaces up to about 200 square feet
  • Medium purifiers will work for rooms or areas between 200 and 400 square feet
  • Large air purifiers are best when you need coverage for 400 to 1500 square feet
  • Whole home air purifiers will clean the air in your entire home using your ductwork

Based on that, assuming you’re not only looking for a purifier for one specific room, a large air purifier will be sufficient for a large apartment /condo or smaller house.

Figure out the square feet you need or want to cover and work from there.

Air Purifier Placement

As mentioned above, the best place for an air purifier is where your family spends the most time. 

It could be in a media room, the kitchen, a home office, or perhaps a bedroom.

But if you have multiple small rooms in your home that would benefit from cleaner air, deciding to have an air purifier in every room makes more sense.

Once you’ve determined where you’d like to place your air purifier, it’s time to do some measuring.

Air Purifier Coverage Area


Since some people are completely math challenged — raising my hand — we’ll follow the KISS (Keep It Simple Stupid) method so everyone will understand.

Air purifier coverage will be based on square feet or square meters, depending on where you live. 

Fortunately, calculating square feet is ridiculously simple — especially for just one room.

Grab a measuring tape and measure the length and width of your room. 

If your room is not a perfect square or rectangle, for example, there’s an alcove, take two measurements and add them together. 

The length times width of the room plus the length times width of the alcove—or whatever.

For example,

Room = 10 x 13’ = 130 sq ft

 Alcove = 2 x 3’ = 6 sq ft

 Total = 136 sq ft

If you hope to clean the air of two or more adjoining rooms, use the same method as above, adding the square footage of each room to come to your final total.

Assuming you’re hoping to purify the air of your entire apartment or home, you probably already know your square footage.

If you’re basing your calculation on the square footage of your home, keep in mind that not everything is always included in this measurement. 

Any finished space like staircases and closets would be included, but porches, garages, and unfinished basements likely aren’t.

And one more thing to keep in mind. When you see the coverage area on the box or literature of an air purifier, it’s not an exact number. It’s just an estimate. 

And depending on the layout of your area, it may be more or less efficient as it gets to the outer limits of the coverage area.

Now that you’re able to determine what size air purifier you need — and whether or not you need an air purifier in every room — there’s still something else you need to consider.

CADR Ratings—What’s That All About?

Another very important consideration is the CADR rating.

CADR is an acronym for Clean Air Delivery Rate. 

Essentially, that means the volume of filtered air the purifier can exchange – how much dirty air gets replaced by clean air in a specified timeframe.

The higher the rating per pollutant, the more it will remove.

If the air purifier you already own or the one you’re thinking of buying doesn’t have this rating, it is neither tested nor certified—and there’s a very good chance it doesn’t meet industry standards.

What Pollutants Do You Need Your Air Purifier to Remove?

Just as air purifiers can clean air in smaller or larger areas, different models also come with different features and filters that will clean different things from the air.

So what do you need to be cleaned from your air? And what are purifiers capable of removing from the air? Will you need an air purifier in every room—each targeting different airborne pollutants?

If that works best for you, go for it.

Here’s a breakdown.

HEPA Filters

Assuming you choose an air purifier with a HEPA filter, these highest-rated filters can capture 99.97% of airborne particles up to 0.3 microns. 

In perspective, 0.3 microns is smaller than a strand of fine human hair. 

And they can remove the following:

  • Bacteria
  • Cigarette smoke
  • COVID-19 (according to the National Library of Medicine, COVID particles range from 0.06 to 0.14 microns)
  • Dust
  • Mold spores
  • Pet dander
  • Pollen
  • VOCs (volatile organic compounds)
  • Wildfire smoke
  • …and more

You may not need an air purifier that removes smoke — from tobacco or wildfires — but you might need something that removes pet dander. Or you may have someone in the house who has a pollen allergy.

So you have an option. 

You can buy a purifier with a top-rated HEPA filter that will remove any and everything, but it will cost you. Or you can choose one with the lower MERV-rated filter that targets what you need and doesn’t cost as much.

But wait. There’s another, even better option.

Most air purifiers only clean or purify the air; they don’t sanitize it. And depending on the severity of a family member’s need for clean air, sanitizing may be required.

If you have a central system, the best option for this is a UV light attached to it. 

Portable air purifiers offer this ability as well. Another option is an ionizing model.

True HEPA vs. HEPA

Don’t get caught up in marketing ploys. 

Marketing aims to make you buy a product, not necessarily tell the truth.

If you’re buying a product headquartered in a country with the highest of regulatory standards—note this doesn’t mean the product is also manufactured in that country—there must be a measure of truth in marketing statements. 

But not the whole truth and nothing but the truth.

Be suspicious if you’re looking at cheap air purifiers on Amazon or any other online retailer. 

If you’ve never heard of the brand name, do some research. There’s a good chance that the product is cheap for a reason. 

There’s also a good chance any claims made in their marketing material could be outright lies.

Does this mean that any product developed and manufactured in some country that doesn’t have the stringent regulatory demands most western countries have should be ignored?

No. It just means you need to do some research. 

Western manufacturers operate under strict regulations—but other parts of the world? Not so much.

So just because a product says the filter is a HEPA filter or True HEPA doesn’t mean it is. And True HEPA is a marketing or branding term. 

Assuming it’s a genuine HEPA filter, it’s the exact same thing as any other genuine HEPA filter.

The important word there is genuine.

Don’t buy anything with a name such as HEPA-Like, HEPA-Ready, HEPA-Type, etc. 

A legitimate, genuine HEPA filter will be labeled and signed off. 

This lets you know it has passed testing and inspection and can do the job it claims to do.


Do You Need an Air Purifier in Every Room? – FAQs

If you’re wondering whether or not you need an air purifier in every room, there may be other questions in your mind as well. Maybe one of these!

Is it okay to leave an air purifier on all day?

Yes. Leaving your air purifier running 24/7 is optimal.

Is it okay to sleep next to an air purifier?

Yes, it’s okay. However, depending on the dB rating, it may disturb your sleep.

Do air purifiers make a room smell fresh?

Air purifiers can reduce or remove some odors, but there is no guarantee they will completely freshen your air.

So, Do you Need an Air Purifier in Every Room?

Having an air purifier in every room is welcome and beneficial, although not really necessary. But ultimately, the answer to that will depend on your space and needs.

If you’re still in the research stage, knowing the relevant details about your room and the air purifier you’re eyeing is essential in buying the right one for your needs.

So be sure to follow the guidelines above!

READ NEXT: Can I Move An Air Purifier From Room to Room?