How Well Does a Multi-Room Air Purifier Perform?

Updated on May 1, 2022 by Joseph D. Nielson

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Improving your indoor air quality is important for keeping a clean and healthy home. But unlike dusting the shelves and mopping the floors, cleaning your air isn’t so easy. This invisible part of your home needs an air purifier. 

Now, we know what you’re thinking. Is one air purifier strong enough to rid the air of pollutants and allergens from your entire home? Or do you really need to place one in every room to stay on top of these contaminants?

In the interest of being fresh and frugal, we understand the appeal of buying a single machine that can do it all. Not only is it cheaper, but you’ll also save yourself the trouble of finding space for a portable cleaner in each room — or lugging one machine from room to room! 

That’s why we’re delivering this guide on multi room air purifiers. We’ll share the essential specs you need to find in an air purifier to make sure it’s up to the task.

What is a Multi Room Air Purifier? 

First, let’s define an air purifier. If you go about Googling this product on your own, you’ll notice most blogs and manufacturers use air purifiers and air cleaners interchangeably, and we’ll do the same for the purposes of this guide.  

An air cleaner is an appliance that sanitizes the air of your home and removes pollutants, toxins, and allergens. It completes this mighty job by drawing air into its chamber and running it through at least one filter. 

In many cases, an air cleaner uses a High Efficiency Particulate Air (HEPA) filter. This specialty air filter removes 99.7% of dust mites, pollen, mold, bacteria, and airborne particles that measure 0.3 microns [1]. 

When one micron is equal to that of 1/1000 millimetres, you know that’s small. 

That measurement is important for your health. It means a HEPA air purifier traps harmful inhalable particles like tobacco smoke, Volatile Organic Compounds (VOCs), and even some bacteria. Research from the Centers for Disease Control and Prevention (CDC) indicates a HEPA air purifier could even decrease your exposure to COVID-19 [2].

Once the air passes through one or more HEPA air filters, the air purifier circulates the clean air back into the room. 

Now, when it comes to a multi room air purifier, it does the same job but on a grander scale. Rather than cleaning the air contained in one room, it removes pollutants in the air of many rooms. If you’re lucky, it could work on your entire apartment or house. 

Why Do You Need a HEPA Air Purifier? 

Let’s face it, the pandemic has changed the way we think about ventilation and indoor air quality. Between the lockdowns keeping us inside more and health authorities recommending limits on indoor gatherings, we’re hyper aware of the air we breathe. 

Unfortunately, that air might not be as clean as you might think. According to the EPA, pollutants are two to five times higher indoors than outside [3]. 

These pollutants can have a harmful effect on your health. In the short term, you might notice you’re extra sneezy or congested when you go about your day. That’s because pollen, dog dander and dust mites can trigger allergies and worsen your asthma. 

However, long-term exposure to fine particles smaller than 10 microns (like those that make up dust mites or smoke) can travel deep into your lungs, increasing your risk of cardiovascular disease, heart attacks, and stroke [4].

Then there are VOCs, which are gases released by the chemicals in furniture and textiles, as well as the aerosols, cleaning supplies, and air fresheners you use every day. These ever-present VOCs could cause a long list of ailments, including throat irritation, headaches, and liver damage [5].

One of the biggest benefits of Air Purifiers is how they reduce these risks of VOCs, pollutants, and allergens. They remove many of these nasty irritants from the air, circulating fresh and clean air in its place.

Is an Air Purifier for Multi Rooms Capable?

So now we’re finally answering the big question. Can a multi room air purifier work? The answer is yes, but with conditions. 

Each machine is designed to cover a maximum amount of space. Whether a particular machine is right for your space depends on a couple of things.

  1. Your Square Footage
  2. The Power of Your Machine 
open-concept living room and dining room

1. Square Footage

Your home’s footprint gives you a good indication of how much air your multi-room appliance has to clean. Knowing this number is important — most air cleaner manufacturers show how much area their cleaners can handle right on the box. 

To find the square footage of a single room, all you have to do is multiply its length by its width. For your entire home, repeat the process for every room and add their sums together. 

2. Machine Power

In the air-purifying world, power or capacity is determined by two primary metrics. The following measurements indicate how well an air purifier will perform in a given room size. 

Air Changes per Hour (ACH): ACH lets you know how many times any HVAC device can cycle through all the air in a room. When it comes to your air cleaner, the sweet spot is 4.8 ACH for any given room — meaning it has to turn over all the air in a room 4.8 times in an hour to be effective [6]. An appliance’s ACH depends on the room’s size, so you’ll need a higher ACH for a larger room.

Clean Air Delivery Rates (CADR): A purifier’s CADR (which falls on a scale of 400–450) represents how much clean air it produces every minute. With CADR, the bigger, the better. One, it removes pollutants in the air at a faster rate. Two, it indicates it can cover a larger area. As a result, this is by far the most important metric to consider when buying an appliance for multiple rooms. 

What to Look for in a Multi Room Air Purifier?

Long story short, keep your eyes peeled for these features when shopping around:

  • 4.8 ACH for your suggested room size
  • A higher CADR
  • A HEPA air filter

What if multiple rooms have a square footage that means it has an ACH lower than 4.8? 

If you can’t find a machine that achieves 4.8 ACH for the combined size of your living room and dining room, it won’t turn over the air as rapidly as the pros recommend. In other words, if your space is too big for the machine’s capacity, you’ll have to think about getting more than one air cleaner. 

However, if a purifier shows it can reach a 4.8 ACH for your living room and dining room combined, you can rely on just one cleaner to do the job.

Where to Place an Air Purifier?

Just like finding the best place to hang your favourite painting or arrange your couch, there’s an art to finding the best location for your air purifier. 

The correct placement can help this appliance improve air flow and reduce pollutants in the air. 

Here are some tips to help you find the best spot in the house.

  • Locate Low Air Flow. You don’t want to place your appliance right next to a window or door you’re constantly opening. This placement means your cleaner will constantly fight against contaminated air without really purifying the rest of the room.
  • Avoid Humidity. Keep it away from humid areas of the home, like your bathroom. High humidity can reduce how well your HEPA air purifier works. 
  • Keep Away from Obstructions. You don’t want to place this appliance too close to furniture or fabric that could potentially block air flow. You also shouldn’t place your cleaner in a corner or under a desk. Your purifier needs a few feet of clearance in all directions for maximum cleaning powers. 
  • Focus on High-Priority Rooms. If you’re worried about your appliance’s capacity, place it in the room that gets the most use. Alternatively, you can put it in the most important room, like your child’s bedroom. An air purifier is a great way to keep your nursery air and upholstery clean. 
  • Leave it Running. An air purifier is designed to run 24 hours a day for the best long-term results. 

Can You Use Two Air Purifiers in the Same Room? 

Sure, if you live in a sprawling open-concept apartment, this could be a great way to ensure you achieve the right ACH and CADR. However, it would be a waste of money if you put two appliances in a tiny room. 

Other Ways to Improve the Air Quality of Your Home

Besides choosing the right sized air purifier for your space, you can help improve your indoor air quality by making some simple changes. Here are some tips that can help you reduce pollutants in the air.

older woman wearing blue rubber gloves while washing her window

Schedule an HVAC System Tune-Up. Your HVAC system controls the air flow of your home, so it’s important it’s working at its best. An HVAC technician can check your furnace and air conditioner to ensure there aren’t any issues.

Replace Your Air Filters. The air filters in your HVAC system work just like the air filters in your air purifier. They trap dirt and pollutants before you can breathe them in, so you want to make sure you keep them clean and ready to absorb debris. 

Clean Often. A regular cleaning schedule won’t just maintain a fresh and clean odour in your home. It will also improve your air quality. Textiles are magnets for pet dander, pollen, dust, and other debris, so you’ll want to give them extra TLC. Next to vacuuming and dusting, laundering sheets, drapes, and pet bedding can help you get a handle on asthma and allergies.

Monitor Your Space. An air quality monitor can let you know if any airborne chemicals, toxins, or other nasty pollutants spike in your home, signalling you need to run your purifier STAT. If you aren’t sure which one to go with, we’ve found out the best air quality monitoring system on the market today.

Together, these habits can help you improve your air quality. But if you want to see the greatest improvements for the least effort, find the right air cleaner for your space — whether that’s one machine or many. 

Remember what you learned about ACH and CADR to make sure an appliance has the power to handle more than one room. If one machine can’t do it, you may have to invest in enough air purifiers to suit the size of your space. 


[1] What is a HEPA filter? EPA

[2] Efficacy of Portable Air Cleaners CDC

[3] Why Indoor Air Quality is Important to Schools EPA

[4] Particle Pollution American Lung Association

[5] Volatile Organic Compounds in Your Home Department of Health

[6] Air Changes per Hour FAQ AHAM Verifide

Joseph and Family
About Joseph D. Nielson

Former journalist and editor for various press groups, I now dedicate my time to reviewing products for the home and family life. When I get time to myself, I enjoy rock climbing, taking my dirt bike for a rip, and most importantly providing my family with the best home possible!