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.

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 bedroom 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 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
Grant Williams

About the author

Grant is a professional engineer by trade and has experience with both maintenance and do-it-yourself home projects. He enjoys sharing his expertise & ideas with others to help them improve their comfort and quality of life. Read more »

Your comments are welcome!

  1. Hi Grant,

    This was a great read and super helpful! I’m wondering if you have any experience or opinion on the Cleanlight Air – I bought one on a buy one get one free deal, and am feeling like I may have been sucked in by fancy advertising and great price, LOL. It’s for use in our spare-bedroom (approx. 120 sq ft) which we use daily (m-f) as an office; and one in our master bedroom (approx. 224 sq ft). We do also have a Shark Air Purifier 4, on our main floor in the living room (open floor plan; whole house sq ft is 1,902). I’m wondering if we would be better off purchasing a second Shark for the upstairs (maybe in the hallway to cover the whole 2nd floor) or two of the Levoit models you recommend above to use in these two upstairs rooms; if the Cleanlight Air models I purchased were maybe not the smartest choice? Should note, I have asthma, both hubs & I have allergies, and pets; non-smokers, but in the PNW where wildfires sometimes really degrade the air quality.

    Thank you for any help or insights. Happy Monday!

    • Hi Melissa and Happy Monday to you too :) Very small purifiers like the Cleanlight Air just can’t move enough air or filter well enough for a home. So they’re not going to do much, if anything, for you. Maybe ok for your vehicle and tiny spaces, but I’d never recommend one for use like you’re describing.

      You definitely would be better off getting a “real” purifier for the areas in your home your mentioned. For what you paid for the Cleanlight Air (even with a buy one/get one free deal) you could have gotten 1-2 small or medium sized purifiers that would help more, even if fairly basic in their features.

      I would definitely recommend aiming for brands (Levoit being one, but there are many others also like GermGuardian and Winix) that provide CADR ratings. They are tested to verify their effectiveness and have ratings on the box or advertising. Especially if you both have allergies which can be rough. Best regards!

  2. I have a living room that is 15 by 30 also my kitchen is the same. Do I get 2 purifiers since we have an open concept downstairs. Half wall between the 2 rooms. Also have a dining room off the kitchen. Ceiling height is 8 feet.

    • Hi, ideally yes unless you get a single large room purifier rated for the total space of both rooms. Either way will work. Best regards!

  3. I’m allergic to mold (aspergillus) and dust. If I have an airfree unit in every room including stairs and landing, will it make me more likely to react to allergens when I leave the house? Thank you

    • Hi Sheila. I’m not aware of any way that being free of allergens will make you more susceptible to them once exposed to them again. It should be the case that you’d have the same response you normally would.

      Best regards!


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