Honeywell Tabletop Air Purifier

Do I Need An Air Purifier For Each Room?

I live next to a busy street, where traffic and dust pollution are rife and when it's springtime pollen is everywhere in the air. So for me and my wife, it was only a matter of time before we decided we are getting an air purifier. However, before we went out and got one, a voice in my head kept asking “won’t we need one for every single room in our home?” This voice eventually drove me to do some investigation and I found there is actually a lot to this. To save you time running around trying to figure this out, here is everything I discovered.

Do you need an air purifier in every room?  Whether or not an air purifier is needed in each room of a dwelling highly depends on its architectural structure and size and the type of air purifier that is being used. Larger estate homes may require an air purifier in several rooms while smaller apartments can do with only one air purifier.

Before my investigation, it only made sense to me that a home needs an air purifier in every room. However, to my surprise, I found that even the biggest homes don’t need an air purifier in every room to keep the air clean. The main setting which I could find where having an air purifier in every room would be necessary is in a house that’s set up like a hotel, with private self-contained rooms.

There are so many factors at play that determine whether you will need a purifier in every room of your home. You have to think about the kind of walls your house has, whether you have a corridor or not, how big each room in your home is and the list goes on. There is no one size fits all answer and the answer really depends on your scenario.

I will explain everything as you read on, but the main idea you should keep on your fingertips is that the way you position your air purifier can maximize the area that it manages to clean across your home and minimize the number of air purifiers you will need.

Keeping this idea on your fingertips, I will start by explaining how your type of air purifier plays a role in determining whether you will need one in every room and then I will tell you about room sizes and architectural structure and thereafter look at other factors that you need to think about and that will help you make a good call.

My assumption here is that you are reading this because you are concerned about air purifiers for your home but everything I am going to tell you here, you can also apply to other environments where you have multiple rooms like office space, bunkers, and guest lodges.

How Different Types of Air Purifiers Determine If You Need An Air Purifier For Each Room

I personally think the most important factor in your decision on whether you need an air purifier in each room is the air purifier technology you choose. There are various technologies on the market and some are able to cover larger room sizes better than others, while some cost more than others.

With doors open, some technologies can easily cover multiple rooms at once while others will even fail to clean the room they are in. If you have multiple rooms to cover you will want to go for an option that will give you the most coverage at the least cost from both a buying, operating and maintenance perspective. You also want an air purifier that can cover multiple rooms. Let's now look at the different technologies.

HEPA Air Purifier

If you decide to get a HEPA filter air purifier more likely than not you will need one in every room of your home. This because of the way they work and their coverage ability. HEPA air purifiers work using a mechanical filtration system and as a result, the amount of air they can clean per hour is highly restricted, especially as the area your device has to clean increases.

They work by using a fan to draw in air through a porous sieve-like cardboard material which traps pollutants in your air.

The more air that gets through your HEPA air purifier the cleaner the air in your room gets. With this in mind, you can immediately see that when your space increases there is more air that your device needs to process but unfortunately it can only deal with the amount of air it is designed to take in.

In other words, if a room is too big a HEPA air purifier just becomes useless. You would either need to get a purifier which can cover a bigger space or multiple purifiers to fit your room size. HEPA air purifiers work best for room sizes of up to 1500 sq ft but if a room gets bigger than this they begin to under perform.

The number of air changes they can do per hour (ACH) drops significantly above 1500 sq ft. Whatever size HEPA air purifier you get make sure it can give an ACH of 3 and upwards to maintain the best air quality in your home.

The other challenge with HEPA air purifiers is that even if you were in a small apartment with 1 or 2 rooms and an open plan kitchen and living room, it won’t be able to clean the other rooms properly when you leave each room's door open. The strong reliance of a HEPA air purifier on airflow just doesn’t allow for this as it is difficult to get air to flow around your home between different rooms, using a fan on a single device.

So if you are getting a HEPA air purifier and you want to ensure clean air across all the rooms in your house, no matter how much space your air purifier can cover, I strongly suggest you get one for each room. If for any reason you cannot get one for each room in your home, get one for the rooms where you spend the most time and the rooms where your main source of indoor pollution is.

Typical sources of pollution in your home include garbage and cooking in your kitchen, the rooms your pets are frequently in, basements or storage rooms. Also if you go for HEPA air purifier, get one with activated carbon to deal with odor and gas pollution.

HEPA air purifiers on their own are only good at dealing with a particulate matter like dust and pollen and ultrafine particulates. You also want to stick to HEPA air purifiers that are labeled true-HEPA.

All the other types of HEPA are substandard and not as efficient at filtering out dangerous particulates in your air. To conclude on HEPA air purifiers, taking into consideration all the caveats about them you will need this type of air purifier in each room to effectively maintain good air quality in your home.

Photocatalytic Oxidation (PCO) Air Purifiers

Unlike HEPA air purifiers, PCO air purifiers not only use a fan to suck air and clean it but also use natural convection to get air through their air cleaning unit. PCO air purifiers also do not use a filter to trap particulates in the air but rather use an oxidation process to completely destroy pollutants in the air turning them into carbon dioxide and water vapor.

This air cleaning process allows the PCO air purifier to not only cover a lot more space than a HEPA air purifier but also to work across rooms when you leave doors open. Typically sized PCO air purifiers can easily deal with estate size rooms and a single device can work for a room as big as 3000 sq ft.

Now, PCO air purifiers will not penetrate through walls or closed doors, but if you do not mind leaving the doors in your home open most of the time, then you can get one PCO air purifier for every 3 rooms. The big assumption here is that your living room and kitchen are open plan and are not separated from your bedrooms by some kind of corridor.

If you have corridors between your rooms, even a PCO air purifier won’t be able to clean air in multiple rooms and you will need an air purifier in each room. You will also need multiple PCO air purifiers in your home if you prefer to keep your doors of your rooms closed.

Ionic & Electrostatic Air Purifiers

Electrostatic or ionic air purifiers, work completely differently from HEPA and PCO air purifiers. Electrostatic air purifiers and ionic air purifiers are pretty much the same things as they work in the same way.  

The only difference is that electrostatic purifiers have a collecting compartment that attracts neutralized air pollutants out of the air using electric charge. Both ionic and electrostatic air purifiers are active air cleaners in that they emit charged ions into the air to go after pollutant particles and neutralize them. We can collectively call them ionizers.

Like PCO air purifiers,  ionizers have quite a great reach and typical home ionizers can clean air in a space of up to 3000 sq ft. They can also release ions across open doors and thus clean multiple rooms but unfortunately, they create a mess. Their air purification process leaves behind thin films of dust on walls and surfaces made up of the particles the neutralized from the air.

Another problem is that they produce ozone as a by-product and this is harmful to your respiratory system. Some people can stand the level of ozone released by ionizers but if you have anyone or pets with an existing respiratory condition you best avoid ionic air purifiers.

The same principle applies as PCO air purifiers for ionizers in terms of getting a device for each room. Get one for each room if you can’t leave doors open all day and if your rooms are too far apart. However, only get an ionic air purifier if you don’t mind cleaning up the thin film of dust they leave behind on surfaces and minor levels of ozone.

Ozone Generator Air Purifiers

Ozone air purifiers work by emitting ozone particles in the air which attack, disinfect and decompose air pollutants. You see, as much as ozone is harmful to your health it is a good cleaning agent and can work wonders in freshening up the air in your home if used properly.

You definitely would not need an ozone generator for every room in your house. Besides you getting terribly sick, if you have small pets you can actually kill your pet if you leave an ozone generator turned on long enough while it's in the room. So the best way to use ozone generators is while there is no one at home.

You turn on and run the purifier once your house is clear of inhabitants and switch it off an hour before anyone gets back. If you have to clean multiple rooms you can run multiple devices at the same time in each room or use a single device by placing it in each room for at least 3 hours according to your devices coverage area capacity.

Unlike other types of air purifiers, ozone generators are a once off type of air cleaner for intense cleaning when the air is really bad in your home. It is unwise to leave an ozone generator running 24 hours a day in your home like a HEPA or PCO air purifier.

I personally do not mess with ozone generators and if I needed to use one I would rather call in a professional cleaning service to come in and give my indoor air an ozone cleanse. So in conclusion, you do not need and you should not even try getting multiple ozone generators got each room in your home.

I have now shown you the key things you need to look out for when it comes to using multiple air purifiers across rooms based on types of air purifiers. As you can see, some types of air purifiers will allow you to cover multiple rooms with one device.

Accordingly, whether you can leave the doors around your house open or not for extended time periods aim to go for the air purifiers that I have shown are able to span across rooms.

I believe PCO air purifiers are a good choice for anyone who wants to cover multiple rooms and they are also great because they don't emit harmful by-products when purifying your air as ionizers do.

Compared to HEPA air purifiers, PCO purifiers perform much better when placed in each of your rooms. PCO air purifiers can use both air and convection to purify the air as opposed to just airflow which limits the ability of HEPA air purifiers to work across rooms.

How Your Room Sizes & Home Architectural Structure Determine If You Need An Air Purifier For Each Room

I already started to touch on room sizes in the previous section. My rule of thumb is to use a PCO air purifier the moment your room gets bigger than 1500 sq ft. You can then choose a good HEPA air purifier for room sizes below 1500 sq ft.

If you decide to stick to HEPA air purifiers, the moment you have rooms larger than 1500 sq ft you may even end up getting multiple devices in just one room. You can get HEPA air purifiers that manage 3000 sq ft and these will do well and give you a great ACH if you place them in each room in a smaller home.

However, the moment you cross the 1500 sq ft line your HEPA air purifiers start to get really big and bulky and can take up quite a bit of space in your rooms. So if you are finicky about having big appliances taking up your space then you will definitely need multiple smaller devices to cover your whole home.

A better option if you have a big home is to get a whole house air purifier. For this option, you have to have an air duct system or an HVAC in your home. A whole house air purifier can be installed at the place where the air is let in through your HVAC system.

This will give you much cleaner air in your entire house. Now you will still get polluted air at much lower level due to efficiency losses but with a whole house air purifier installed all you will need in addition is a couple of portable air purifiers you can move around to the rooms where you spend the most time in as opposed to getting an air purifier for every single room.

That said not everyone has air ducts and an HVAC system. If for any reason you cannot get a whole house air purifier than you have stick to getting an air purifier for each room to cover your whole house. This is made even worse if you have concrete walls separating rooms minimizing airflow across your home.

Here is a guide on what size air purifier and the minimum number you would need for your home based on the size of your home. These minimum figures will give you acceptable air quality levels in your home but if you want even better air quality you will still need one each room especially if your home architecture restricts air flow. The minimum set up you should have is as follows:

  • Small apartment or lofts (300 to 500 sq. ft.) – 190 ~ 320 CADR
  • Medium apartments (700 to 900 sq. ft.) – 2 purifiers with a total CADR between 450 and 580
  • Larger apartments (more than 1,000 sq. ft.) – 2 or 3 purifiers with a total CADR of 650 or higher

CADR stands for Clean Air Delivery Rate. Don't forget that the sq ft here assume your home has a height of 8ft. If you have a higher ceiling you have to increase your air purifier size. These sizes apply to all types of air purifiers but as mentioned earlier your standard home PCO air purifiers generally come with a capacity of 3000 sq ft and you won't need to worry much about coverage if you get a PCO air purifier. Just make sure to check the coverage specs when getting one.

Other Factors To Consider About Getting An Air Purifier For Each Room

How Many People Are In Your Home?

A circumstance where you may not need an air purifier in each room is when you live in a big home alone or with one other person. I am imagining a 5 bedroom home here with 2 people. In such a home you would need at least 2 or 3 air purifiers. One for each bedroom you sleep in and another for your living room.

If you a separated kitchen then an additional one for the kitchen but you could just use an air curtain to prevent the air from the kitchen going to the rest of your home. On the other hand, if you have a full house then get an air purifier for every room. Also get an air purifier for each room if you live in a 2 bedroom apartment and there are 2 of you in the home.  

What Do You Want To Clean In Your Air?

If all you are concerned about is odors in your home you may actually not need an air purifier in every room. In this case, you just need to identify the room where the odor is coming from and place your air purifier there. Common places where odors come from in a home include your kitchen, toilets, basement, pet rooms and storerooms and you will be pleased to know there are air purifiers specifically designed for toilets.

The other thing you could be trying to fight is mold and mildew. Just as you would for odors place your air purifier in the room where the mold is building up. If you have a basement though I think it's always wise to have an air purifier down there. In addition to placing an air purifier in the room where the source of pollution is, also place one in each room where you spend the most time e.g your living room and bedroom and for some people the kitchen.

How to Position Your Air Purifier?

The way you position your air purifier is also very important. This could save you from having to get multiple air purifiers. A very strategic position for an air purifier, especially a PCO air purifier is at a point where it is nearest to as many doors as possible without any obstruction.

You may find your air purifier manages to keep air in multiple rooms clean even without living doors open the whole day just by placing your purifier strategically.

To get the most out of your air purifier whether you have one in each room or just one room, you have to place your air purifier away from obstructions. Do not put it under tables or shelves or behind your sofa or in a corner. This will obstruct airflow and minimize exposure of your air purifier to air through convection. Look to place your air purifier in a central and open space for optimal room coverage.

You can discover more about positioning your air purifier effectively here.

How To Operate Your Air Purifier?

How you use your air purifier is also very important. No matter how many air purifiers you have set up if you do not maintain your devices they eventually become inefficient and stop cleaning your air. You have to ensure you change your air filters or air cleaning unit of your purifier in case its a PCO type purifier as instructed in your device's manual.

The way air purifiers work is that once you turn them off your room's air immediately gets dirty again. So make sure you get an air purifier that you can run 24/7. If you are worried about your energy bill, air purifiers consume less energy than your fridge. So if you can keep your fridge on all year long you can manage an air purifier even when you have multiple running in your home.

The biggest cost you will face with air purifiers is filter changes especially when you have a device in each room. There is no running from this and this will make or break your mission to keep your air clean across your whole home. Make sure you can afford US$20-150 filter changes per device before you head out and get one for each room.

Another thing that will save you time and money is to get smart devices. If you have multiple air purifiers, you do not want to be running around adjusting settings. It not good use of your time and you can easily forget to adjust one of the devices.

So why not get a device that can adjust itself and you can also control remotely from your phone or laptop. There are devices with air quality detectors on the market that self adjusts to increase their cleaning intensity according to how polluted your air gets.

These devices will also warn you when you need a filter change so you don't have to constantly run around checking. There are a couple of other factors to consider when running devices in multiple rooms but I found these are the main ones that could make or break your decision from an operational perspective. So pay close attention to these.

The Ultimate Strategy for Deciding If You Need An Air Purifier In Each Room

I have covered a lot of ground in this post. In case you get information overload or the details outlined in each section are hard to follow let me leave you with a simple strategy to follow when you are making your decision on whether to get an air purifier for each room. Here are 8 key summary points to guide you.

  1. Your aim when it comes to covering every room and maximizing the air quality level in your home should be to maximize the coverage of your home with as few devices as possible.
  2. The type of air purifier that can possibly help you get the most coverage with the fewest number of devices is a PCO air purifier but these devices are much more expensive. Go for PCO air purifiers in your home if you have 3 or more rooms.
  3. If you have less than 3 rooms (e.g. 2 bedrooms a living room and open plan kitchen) having a HEPA air purifier in each room will prove more cost effective than getting a PCO air purifier.
  4. If you live in a house alone or share a room with your partner, you may only need an air purifier for your living room and bedroom and the other rooms can do without or you can get an extra portable air purifier to move around when using your other rooms.
  5. Get an air purifier for each room where someone spends over 3 hours and for rooms where your source of air pollution is coming from, especially basements.
  6. In a home with an HVAC system or air ducts running through your house, get a whole house air purifier in addition to air purifiers in the rooms where you spend the most time in.
  7. If you mean business about air quality the most you can do is get an air duct or HVAC whole house air purifier with PCO or activated carbon HEPA air purifiers in each room.
  8. Lastly, make sure to go for smart devices to save you time and money in operating and maintaining multiple devices.

With these 8 points, I think I have covered everything important you need to know before you get an air purifier for each room in your home.

I hope you found this post helpful. Post any question you have on this matter in the comments below and I will get back to you as soon as I see it. If you are wondering which brand of room air purifier to get, check out my recommendations for room air purifiers here.

About the Author


Jean is a research economist by profession and he runs Fresh Air Genie. He is enthusiastic about maintaining good air quality at home and on the go and he shares his knowledge about this here at Fresh Air Genie.


  1. Hi Jean-Baptiste,

    I’m some sort of an air purification buff, and I just can’t resist the idea of reading a good article in my area of interest whenever I come across one. I agree that some air purifiers are huge and can clean areas as big as the whole house. But I’m not sure the idea of a whole-house portable room air cleaner is a very good one. Why? Because air purifiers are designed to work best in rooms that are sealed off. No matter how big on’s purifier one might have, there’s always going to be that little nook or cranny that won’t get the treatment.

    I think I like your idea of using a whole-house air filtration system better. I’d buy a device for each room if you you don’t want to go the whole-house air filtration route.

  2. Hi Jean

    I currently live with my fiancé and her family. Her father smokes in the house and I want to protect myself from second hand smoke. I can’t afford to buy a air purifier for every room so that is out of the question. Would it improve the air to move the air purifier into the room where I am at the time? Any other advice would be great.

    1. Author

      Hello Robin. Good question. Its more effective if the air purifier stays in one room and on all the time. But you can definitely move your air purifier around. However its not worth it if you are in a room for an hour as most air purifiers take up to three hours to clear the air completely. So wherever you place your air purifier be prepared to wait a couple hours before you notice a difference. Also make sure you get an air purifier with a large activated carbon filter to suck up all the harmful cigarette smoke particles and odor.

  3. I am mostly looking for an air purifier where I do not have to do lots of manual controls and what not. You are seated in the house and really want the air purifier to do its thing with a simple remote control touch. Not those manual old things where you have to turn on and off and put on those turbo settings. Remote or even bluetooth is the way

    1. Author

      Check out our recommendations section. Those are most certainly available

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