Do I Need An Air Purifier In Every Room? An Informational Guide For Everyone

So you’re considering buying an air purifier. But perhaps you want to breathe better, cleaner air in more than just 1 room.

If you’re thinking about buying more than one you may be asking yourself, “Do I need an air purifier in every room?

In this post, I’ll go into more detail and cover the facts you need to know before spending money. I’d like you to get the most benefit from your buying options and to get the best benefit per dollar spent.

Do I need an air purifier in every room? The basic answer

Before I go into more detail, here’s the short answer.

Air purifier room facts

The simplest answer is that you don’t need an air purifier in every room.  There are more things to consider, too, before buying & using air purifiers in multiple rooms:

  • The number of rooms which you regularly occupy and need an air cleaner for
  • Air quality problems you need relief for
  • Room size (in square feet) for matching with the correct model of purifier

However, you need to buy the right kind (or a combination of different kinds) for your needs. Additionally, you need to buy air purifiers with enough coverage for your particular home & needs.

You’ll also need enough of them to handle the air space volume (room size coverage, in other words) where you have air quality problems.

What to know before buying air purifiers

If you want the air inside your house to fresh and free of irritants, it only makes sense to place air purifiers in all rooms… right?

Well, not necessarily! 

Before making a decision, you need to consider several factors that affect the “hows” and “whys”:

  1. Budget
  2. Air cleaning needs
  3. Rooms needing coverage
  4. Air purifier room size

1. Budget

To be frank, placing an air purifier in every room would be pricey. From the very beginning, you really need to think about your expectations and air cleaning needs vs. the amount of money you can afford to spend.

While this may vary from home to home, the average house has about five rooms. How much are you able to spend to get air purifier coverage for your home and in multiple rooms?

Give this some thought before you go shopping online. Some people might be inclined to buy cheap ones so that they can place air purifiers in all the rooms. This is actually a mistake that might not seem obvious at first glance.

Cheap, low-spec air purifiers can actually be worse than having no air purifiers at all.

There are lots of reasons why, but it’s mainly because they do a poor job at cleaning the air and ultimately you’ll be unhappy with the results. In some cases, some products sold as “air purifiers” do little besides blow air and some produce by-products that can irritate the throat and respiratory system.

If you have to spend extra money later to buy better ones, that means you’re actually losing money – not saving it!

Cheap ones will only circulate dirty, unfiltered air through your house to the point that you would probably be better off without one. A single air purifier of good quality is worth more than several low-grade ones that work poorly.

Remember this: Quality over quantity. Every time.

What you can expect to spend

That being said, for a decent budget air purifier you can expect to spend about a bit under $100 for each.

Higher quality models that are best sellers and have amazing buyer satisfaction are only a bit more and sell for around $140-$200 depending on room size coverage, features, and performance.

More advanced models offer a lot more convenience and can even run in automatic mode or include a remote control.

Don’t worry! You don’t have to be rich or spend a ton of money to keep the air clean in your home. There are some great options that are affordable – you just have to be careful when buying. I’ll cover that more in detail below.

2. Your air cleaning needs

Diagram showing common air quality problem sources

A wide variety of contaminants – or combinations of those – need a “real” air purifier that will permanently remove them from your air. Some problems, like dust mites, require a HEPA filter. Odors and airborne chemical substances need an activated carbon filter to cleanse the air successfully. Think about what you specifically need relief from.

Not everyone has the same air quality needs. For example, if you have pets you’ll have slightly different requirements than someone who is dealing with dust.

A person with allergies or asthma problems, for example, will need different features as well.

Pet owners can sometimes find certain models with special filter versions available for their product.

Want to learn more? I’ve written a great post called “What Kind Of Air Purifier Do I Need?” here which goes more into detail.

Ultimately, it if involves removing odors, you need one that features an activated carbon filter. For general applications, at a minimum, you need a High-Efficiency Particulate Air filter (HEPA) model with sufficient room coverage.

Special features

If you have particular health issues or are susceptible to colds or other sicknesses, you might consider a model with a germ-killing feature. Some do this with an ionizer or ozone generator.

I don’t recommend these for people with respiratory problems, although ionizers are proven to greatly reduce airborne germs that cause sickness.

A few offer germ-killing features such as ultraviolet light (UV) light to reduce the chances of you contracting an illness.

Others offer advanced convenience features like self-off timers, a quiet mode, and so on. Some even offer smartphone control and air quality reports while you’re away!

3. Rooms needing coverage

Do you spend a considerable amount of time inside your house? Which rooms do you stay in the longest? Which rooms do you seldom use?

An average person spends the longest time in their bedrooms, followed by the living room. Most likely the time you spend in other rooms would pale in comparison. Air purifiers placed in rarely used rooms are useless so they would be a poor use of your money.

What’s the use of purifying the air in an area you don’t use? Don’t be concerned about rooms that are rarely entered. Much as you seldom enter them, so the same is true for air contaminants.

Unless some of the areas of your home have exposure to the outdoors (and particles brought inside) or other sources of poor air quality, it really shouldn’t be much of a concern.

Thinking about purifier placement

Concentrate mainly on adding air purifiers to the main areas – and areas in between – that you spend the most time in.

The areas where you, your pets, or others predominantly reside are the rooms that need air purifier coverage. Placing them in between means that other areas will have their air cleaned as well.

Although they’re rated for certain size rooms, air purifiers will still circulate air from other parts of your home. It does take some time, but additional rooms will have their air purified as well if air can circulate sufficiently.

4. Air purifier room size – how to find the square feet measurement

Room size measuring example

Most air purifiers sold specify the recommended room size they can clean in terms of the size of the room. This is usually stated in square feet (sq. feet, or “ft^2”).

Others may optionally state the room air coverage in cubic feet, which is very similar to room size except that it also takes into account the ceiling height of a room. Unfortunately, some may not specify this coverage ability clearly.

If a purifier doesn’t specify room size, assume it is generally good for a small room.

Before shopping, you need to estimate these rough numbers using some easy math. Don’t worry, as even if math isn’t your strong point, it’s not hard at all.

Estimating the air purifier coverage you need for a room - examples

1.  Estimating the air purifier coverage size in square feet for a bedroom:

Room width x room length =  10 feet x 15 feet room size = 150 sq. feet (150 ft^2)

2. Estimating the air purifier coverage size for a bedroom in cubic feet (air space volume):

Room width x room length x ceiling height = 10 ft x 15 feet x 15 feet = 2,250 cubic feet (ft^3).

After estimating the room size coverage you need, write it down in your notes. That way you’ll be ready before shopping when evaluating choices and you can verify it’s close to your room size.

Air purifier coverage specs are estimates

The room size listed by different manufacturers are estimates. Just like any other kind of estimate, it’s impossible to get the exact number – but the great news is that you don’t need to. The idea is to buy an air purifier based on the room size coverage it states it can provide that is close to the room or rooms you want to use it in.

Don’t worry about getting it perfectly right. All brands take time to circulate and clean all the air in a room, so even if the listed coverage is a bit below what the product you buy is rated at, it will clean it eventually.

Just remember it doesn’t need to be perfectly matched. Your goal is to buy a purifier with close to or greater than a coverage rating of the room you want to use it in.

Air purifier CADR ratings explained

What is a CADR rating?

A purifier’s Clean Air Delivery Rate is a measured, numerical way to express how effectively a purifier can filter a room’s air.  Introduced by the Association of Home Appliance Manufacturers (AHAM), the CADR rating is an industry standard for measuring the airflow of filtered air.

The main benefit of a manufacturer-provided CADR rating is that you know the purifier has been tested in a certified test lab by following industry guidelines.

In other words, the CADR rating is a figure of measurement that is the volume of filtered air delivered by an air cleaner. The higher the numbers (listed for smoke, dust, and pollen) the more effective it is at filtering.

Why it’s helpful to know

Generally speaking the higher the numbers or numbers, the better.

CADR rating example label

Shown: An example CADR rating from a purifier. Not all manufacturers provide them or only provide them for certain models (typically higher-quality models include them).

Products sold with a CADR rating benefit you because you know they have a proven amount of square footage air filtering coverage. There’s no guessing and it is a good indicator of a quality product with demonstrated filtering ability.

Higher ratings for the tobacco smoke, dust, and pollen numbers are a sign that the unit will more quickly purify the air than a similar unit with lower ratings.

If the ratings between are the same between two products then the filtering performance is the same.

Air purifier types: portable vs. whole house vs. wall-mounted

Levoit LV-H132 Vs Germguardian AC4825 comparison image

Examples of two popular portable (floor use) air purifiers. Floor purifiers are the most common and are often the best choice for most people.

“Whole house, portable, or wall-mount air purifiers…which one should I use?”

You’ll likely be faced with this question as you set out to buy an air purifier. It’s actually pretty simple, but it’s something you may need to think about in advance.

Portable models (used on the floor or a shelf) can be moved around as needed while whole-house systems cover the full interior of your home. Wall-mounted units are attached to walls and can be placed out of the way.

Here’s a general overview of their respective advantages and disadvantages:

Pros and cons lists for the general placement types of air purifiers

Portable (floor or shelf) air purifiers

  • You can move them from room to room
  • Ideal for those on a budget (You can buy one and bring it along as you switch rooms, even take it to work!)
  • If you buy a model with low space coverage it may not work well in other rooms
  • You could decide it’s a hassle to drag one along every time you switch rooms

Whole house air purifiers

  • Covers the airflow system of your entire house – especially larger interior spaces
  • Works as one whole system (It isn’t necessary to purchase several units)
  • Heavily reliant on the HVAC system
  • Expensive

Wall mounted air purifiers

  • User-friendly (Commonly controlled using a remote control)
  • Works as one whole system (Not necessary to purchase several units)
  • Requires an installation process
  • Fixed in place (If not installed optimally, it could be less efficient)
  • Not flexible in use

What type of purifier should you buy?

The best air purifiers use a true High-efficiency particulate air (HEPA) filter along with a pre-filter and odor absorption feature. These types are very effective at removing airborne particulates of nearly all kinds. Avoid ionizers and ozone generators sold as “purifiers” as many are ineffective and can even cause health problems!

It basically comes down to personal preference. However, generally speaking, most people buy a moderately priced portable model. Many of those available today provide great coverage and air cleaning ability. You can also expect good reliability and fairly low maintenance costs.

You’ll also want to buy a model with a true HEPA filter for the best air cleaning performance.

When getting ready to buy a floor model or HVAC/whole-house purifier product, buy one that works using HEPA filters.

Avoid ionizers and ozone generators as at the minimum they’re not very effective. In the worst case, they’re potentially harmful to your comfort and health. I’ve had several readers report they’ve had very bad discomfort, coughing, and irritation from HVAC products sold as “air cleaners.”

These were ionizers or ozone generators sold with fancy marketing terms, rather than good, quality design and performance.

A standard filter-based purifier can’t cause these kinds of problems, and are nearly always a much better buy, too!

Portable air purifiers are best for those:

  • With a smaller budget
  • Living alone
  • Who are new to purifiers or don’t want to deal with installation hassle & secondary expenses
  • Are renters or may sell their home later
  • Who want additional special features like Wi-Fi control and others

Whole house purifiers are best for those:

  • With a large budget
  • Living in a house with a pre-existing HVAC system
  • Willing to pay secondary costs for installation and maintenance
  • Who wants the most air cleaning that money can buy

Wall mount purifiers are best for those:

  • With a large budget
  • Living with multiple housemates or a family
  • With specific filter & technology needs
  • With no need for extra features and air purifier placement flexibility

Where should I put my air purifier?

Image of Levoit LV-H132 air purifier in bedroom

Since most people reading this will opt for a standard portable air purifier, I’ll cover the main things to know about those after buying one and getting ready to use it.

Generally speaking, bedrooms and the living room are the best locations to place them.

Definitely place them in rooms that have the most traffic coming in from outdoors or which are periodically exposed to sources of external contaminants like outdoor pollution.

If your pets mainly stay in one room most of the time but do move about (like to your bedroom) you might consider putting one in between rooms.

If you find yourself having allergy symptoms in a particular room, that’s a tremendous clue that allergens are airborne there and you need a purifier in that area.

Air circulation

Don’t place a purifier where air cannot circulate throughout the room well.

For example, don’t place them in areas that are closed-off from airflow or obstruct the flow of air through them. Purifiers work by drawing in dirty air, filtering it, and blowing out the newly freshened air so it’s critical to make sure they have easy access and enough space.

Many models recommend 15″ to 24″ space between them and walls or furniture, for example.

Noise levels & light brightness in other sleeping & study areas

Image showing Levoit Core 300 air purifier in a dark room

If you’re sensitive to light and sound when sleeping or concentrating like I am, definitely consider buying a model that has minimal noise production. Several very good products today have the benefit of allowing you to use them in your bedroom overnight without being disturbed. Otherwise, consider moving it slightly outside of your room.

If you stay in a certain room for sleep or need to concentrate for work or studying, consider placing the device just around the edge of the open doorway or slightly out of the way.

While many sold today have a special low-noise “sleep” mode or other low-speed settings with minimal noise produced while in use it can still be an issue for some of us. This includes me!

I recommend therefore ideally buying a model you know won't produce distracting noise or simply move it into a slightly different area.

Additional air purifier placement tips

Image of child in living room with air purifier

Always read the owner’s manual before deciding where to use it!

Don’t forget that reputable brands are well-tested and the manufacturer sometimes recommends the best locations for optimal air cleaning.

Here are a few other things to think about:

  • Don’t put air purifiers in the corner unless otherwise specified as acceptable
  • Try to avoid leaving windows open for very long
  • Make sure your purifier has 1-2 feet clearance (minimal) for best efficiency
  • Keep it a distance of 6-10 feet from the head of your bed
  • Point the output side of the purifier in your direction
  • Make sure the room size coverage of the one you buy is fairly close to, or larger than, your room size

In summary: Do I need an air purifier in every room?

  • No, you don’t. You only need enough to cover the size of the rooms you’ll mainly be staying in or have air quality problems in
  • Estimate your room size and buy products with room coverage close to the size you found
  • Buy quality models and place them in the right locations, positioned properly
  • Most people are fine with a portable model that’s moderately priced. Consider buying one with a germ killer if you are susceptible to sickness or other health problems
  • A good rule of thumb is to start with 1 rated for med. size rooms (living room) and use a smaller model for each bedroom

Levoit Core 300 review editors choice badge product imageFor the average person, I recommend choosing a model that’s a well-rounded combination of price, features, and performance. The new Levoit Core 300 medium room purifier was a great model I recently reviewed.

Find out here why it's one of the best new air purifiers you'll find at Amazon.

Additional reading

As I mentioned earlier, don’t stress if you’re on a budget. I’ve written a helpful guide here with 5 of the top air purifiers under $100.

Be sure to check out my other helpful guides like this one if you have pets or this post if you have a dust mite problem.

Your comments are welcome!

  1. Thank you it was very helpful but hoping you can help me! I’m looking for an air purifier to get rid of smoke (cigarettes and weed coming from 2 apartments) and found one but confused about size.

    I live in a bachelor (1 room) apt and it’s L-Shaped. Kitchen is separate, but beside main room and the kitchen has a window. Do I need to configure an air purifier to accommodate the kitchen because of the open window? If I use a curtain to block the window does it make a difference for unit size?

    Total Area 255sqft: Main room (186sqft) plus area off to side (13sqft), and kitchen (56sqft).

    I was looking at a small unit (Austin Air HM250) manufacturer listed as 700sqft, but I read somewhere it’s better for 235sqft. Is that sufficient?

    • Hi Alice. Well my first comment is that you shouldn’t be leaving the window open if you’re using an air purifier as they work by circulating the room air and cleaning it as they go. Leaving a window open keeps that from them working as intended.

      A curtain won’t prevent air from entering a room via an open window.

      Regarding the Austin Air HM250, that would certainly do the job and looks to be a very competent unit, but that’s a heck of a lot of money to spend plus replacement filters are $360 when I checked. That’s an absurd amount of money for a replacement filter.

      It’s absolutely necessary to replace filters as for absorbing odors & smoke (etc) the carbon filter has a limited life, after which they lose their absorption ability So it’s important to take filter costs into consideration.

      My suggestion would be to look at a great (and affordable) unit like the great Winix 5500-2the Winix 5500-2 which has a real pellet carbon filter and is a really good purifier. Filters are affordable, too. It has an odor sensor which can adjust fan speed automatically.

      You need a very good carbon filter when dealing with smoke & odors.

      If at all possible, try to get you neighbor’s marijuana use stopped or have them do it elsewhere. I know how you feel as I had this issue before and had talk to others as it seeped into my place via my air conditioner vents. It was definitely bothersome, but I suppose it depends on your local laws, your landlord (if you have one), and how agreeable your neighbors are.

      Hopefully this helps, and best wishes!

  2. Thank you
    My grandsin has asthma and i needed a small one for his room. With the coronavirus in us being stuck in the house we spend a lot of times in our rooms. So I went and bought a Febreze air purifier today for my grandson’s room but our bedrooms are so close together that I just put it in the hallway. Thank you for being here so I could read what you had to say about what kind to use

  3. Hi I live in a house which has two floors and with an opening between the two floors where the stairs go up. There are two large rooms of 70 square meters each. Have thought about buying a Philips 3000I series air purifier. Can it handle the two compartments if it is on the bottom floor or is it better to buy two Philips 2000I series and place one on each floor. the opening between the two floors must be closed for the best effect ??. What would you recommend. Thanks in advance Leon

    • Hello, Leon. It would actually be better to have two of the 2000i (or some similar quality purifier, with similar coverage) with one on each floor. You won’t need to keep the stairway closed in that case.

      I’m not sure what’s available where you are, but if the Winix line of purifiers is available there you could potentially save some money. Those are very good ones.

  4. Hi I live in a house which has two floors and with an opening between the two floors where the stairs go up. There are two large rooms of 35 square meters each. Have thought about buying a Philips 3000I series air purifier. Can it handle the two compartments if it is on the bottom floor or is it better to buy two Philips 2000I series and place one on each floor. the opening between the two floors must be closed for the best effect ??. What would you recommend. Thanks in advance Leon

  5. Hi Jack. I thank you for your answer. I have now researched winix zero pro and I can buy this in Ukraine. Price is also okay. $ 350 and I plan to buy 2. winix zero pro. Is that a good choice

    • Privet/Привет, Leon! (Hello Leon). Yes, the Zero is a nice model and the features are very good – same as on some of the companion models sold here in the USA that I’ve tested (5500-2, 5530-2). I think you’ll like them a lot.

  6. I have an older house with two floors 2800ft first floor lg living room and dining room kitchen and breakfast room and tv room there is also 1bedroom and converted office was bedroom. Upstairs we have a hall and two bedrooms the office, bedroom breakfast room and tv room are used heavily and the upstairs two bedrooms are used. i was thinking 2 portable purifiers that can be carried from room to room what do u think thanks george

    • Hi George. I don’t think carrying them room to room would be a great idea unless you mean to leave them there for long periods of time to run once they’re in place. That’s because they need time to circulate the air in a room because it takes some time for them the circulate & clean all of it.

      You could do that in that case, sure, mainly using them in the rooms you use the most. You can also get some of the auto-sensing models like from Winix that will go into a low-energy once they sense the air is clean and ramp up when they sense the air needs cleaning. They can be moved as well, just that they’re a bit bigger.

      I hope that helps!

    • Hi Pat. I would depend on the square footage of the rooms you’ll want to cover. That’s easy to find, though. Just roughly measure the width x length for each room.

      Two medium size units may be enough, but it depends on their particular room size coverage (most provide that in their specs).

  7. Hi Grant. Just came across your useful website. My daughter is allergic to pollen, dust and pet dander. We don’t have issue with smoke or other air issue. For 40’x14′ room, should I get 2 Medify Air MA-25 or one MA-40? We have a Blue Air 411 in her 13’x13′ bedroom that has been running 24/7 since Sep 2020. Thank you very much! Eka.

  8. I have 20’ ceilings in the living room only (goes up to 2nd story) the the dining room and kitchen area have 9’ ceilings. The bottom floor is open and all bedrooms on top floor along a hallway. Will two air purifiers be enough if I place one downstairs and then one upstairs in the hallway?

    • Hi Angel. How big are the rooms roughly in terms of width and length? It sounds like you’ll need some rated for larger rooms. Two large room purifiers should do the job; less so ones rated for medium size rooms.

  9. I have an old musty house. We have replaced all but one rooms flooring. That helped some. We have gotten use to the smell so it wasn’t as noticeable. I washed all my clothes for a trip except a few things that had been hanging in the open ( because there’s only one closet in my whole house ). When I opened my suitcase at my destination, I was very sad to smell the Oder from my clothes. It wasn’t my suitcase. The rooms are broken up throughout the house. No hallway. 1200 sq ft. Any suggestions?

  10. Dear Grant
    I have a lung condition called Bronchiectasis , I live on quite a busy street but I don’t open bedroom windows , do I still need an air purifier?and would I benefit from wooden flooring rather than carpet ,? my bedroom is 4.5 metres by 4.7 metres ? Thank you so much Alice

    • Hello Alice. If your condition can be aggravated by airborne contaminants, then yes a purifier can help. But also they help healthy people breather better anyway, too, so it’s not just for those who have respiratory issues.

      4.5 x 4.7 m is about 15 x ft, or about 225 square feet area room size. So you’d want to get a model based on the manufacturer’s recommended room size which is usually listed on the box & specs. I’m not sure what models you have where you like but the Winix brand is very good.

  11. Hi Bruce.

    I truly appreciate all of your research and insightful comments. I wish I could figure this out on my own. I see how helpful you’ve been to everyone else.

    GOAL: Solely to remove cat allergens

    ROOMS and LAYOUT…NYC Apartment

    1. 11 X 22 Bedroom
    2. 3 X 20 (with 6 x 3 turn in to 2 other Bedrooms and Bathroom)) Hallway
    3. 11 X 14 Bedrooms
    4 11 X 22 Living Room
    5 6 X 22 Kitchen
    6. 6 x 9 Bedroom (off kitchen)

    Please tell me what you would recommend.

    Thank you.

    • Hello Shannon that’s 884 square feet in total. You could use one air purifier that can handle that size (1,000+ square feet rated for example) or 3 to 4 smaller purifiers between rooms also. That could be 3 rated for 300+ sq. feet or 4 rated for ~220 sq. feet.

      It’ll probably end up being more economical to use a good one rated for close to 1,000 sq. feet.

  12. Oh dear, I addressed you as Bruce for some unknown reason when your name is Grant.

    My sincerest apologies.

    Please refer to post above for my question about my daughters cat allergies and the best way to clear the air in our house. The cats do go in every room.

    Thank you, Grant.


Leave a Comment