Our verdict:
There is no solid yes or no answer to this question. The answer to this question will depend on a couple of different factors such as how big your home is, the CADR (Clean Air Delivery Rate) of your air purifier, what issues you are having with your current air quality, how many people live in your home, budget and what features you need from an air purifier.
Air purifiers have justified themselves as a “must-have” device in the home. The extensive benefits of running a purifier in your home prove that you can live with clean, healthy air.
Whether you live in a polluted area (indoor or outdoor), suffer from allergies, reside in a smokey or dusty home, or simply want all the health benefits from uncontaminated air, an air purifier will help with your issues. But how many air purifiers will you need?
In this article, we’ll look into all you need to know about how air purifiers work, room coverage, CADR and filter lifespan and answer the question, Do You Need An Air Purifier In Every Room?
How Do Air Purifiers Work?
The air quality in your home might not be as good as you think. Even with regular cleaning, harmful pollutants can sit undetected in your environment. Running an air purifier with a HEPA filter in your home is the best way to remove invisible toxins making your air healthier.
When you boil it down to the bare minimum, all air purifiers are a filter attached to a fan. Contaminated air flows in and passes through the filter removing the pollutants and leaving you with clean air. Of course, the units you buy in the stores are much more advanced than that, but the principle is the same.
The most effective air purifiers on the market are those that use HEPA filters to remove the microscopic particles that linger in the air. HEPA-grade filters contain a maze of tightly woven fibers that stop harmful pollutants from passing through.
Most units on the market also contain a pre-filter to tackle larger contaminants like dust and hair and an Activated Carbon filter that removes odors and VOCs (Volatile Organic Compounds) through a process called adsorption.
If you want to know more, check out our page, How Do Air Purifiers Work? where we go into a lot more detail on the subject.
How Many Air Purifiers Do You Need?
Now we know how much air purifiers can affect air quality, let’s look at how certain variables will determine how many units you’ll need in your home.
When we break down these factors individually, you will see why they are essential when calculating if you need an air purifier in every room.
🏠 How big is the space you want to purify?
This is one of the main things you need to work out when buying an air purifier. If you get the wrong unit for the size of your space, it will either not clean the air effectively (if the unit is too small) or use a lot of energy to run and take up floor space (if the unit is too big).
Air purifier manufacturers know this information is essential, so (most of the time) they will tell you what size space the unit is designed for, usually measured in square feet. This can vary massively from unit to unit and doesn’t always follow a pattern of “the bigger the unit, the larger space it will clean.”
Before purchasing an air purifier, measure your space. Will the unit you’re looking at cover the area you have? Depending on these measurements, you may only need a single air purifier to cover your whole home, or you will need to run more than one to ensure the air is cleaned in each room.
CADR (Clean Air Delivery Rate) also plays a crucial role in how effective an air purifier will be in your home. CADR measures how much air a purifier can clean in a certain period. An air purifier with a high CADR is more efficient than a unit with a low CADR, which will have to work harder to clean your space.
Remember: Not all air purifiers clean at the same rate, even if they have the same size room coverage. We have a list of what we think are the best high CADR air purifiers that is worth looking at before you purchase a unit for your home. |
The CADR (shown as CFM) is commonly found with the other unit specifications, so it shouldn’t be too hard to find.
If you want to know more about the importance of CADR, check out our page on What Is CADR Rating? where we delve further into the subject.
A good rule of thumb is: –A home from 300 to 500 sq. ft. – One unit with a CADR of at least 150 CFM –A home from 500 to 900 sq. ft. – One or two units with a combined CADR of 300 to 500 CFM –A home More than 1000 sq. ft. – Two or three units with a combined CADR of 600 CFM or higher |
👨👨👧👦 How many people live in your home?
The more people coming in and out of your home will impact the number of contaminants being introduced to your environment, compromising your overall air quality (especially if doors/windows are continually open).
If multiple people are breathing the air, you will need either a unit with a high CADR or more than one to cover different areas of your home, maybe even one for each bedroom.
📖 Case Study In my home, with our diverse schedules, we cook meals at different times. Many odors and other contaminants are being created in one room alone. With all that activity, we needed a unit specifically for the kitchen to handle the extra pollution. |
👃 What issues do you want to resolve?
As well as size and space, you need to consider why you need an air purifier in your home.
❓ Do you suffer from allergies?
❓ What is the source of contamination?
❓ Is your home dusty or has mold and mildew growth?
❓ Do you have pets that shed dander?
If the reason has something to do with poor air quality, an air purifier is the obvious solution, but it all depends on the issue and how much of your home it affects. The more severe the issue is, the higher CADR a unit requires, or multiple units should be considered.
📖 Case Study My friend suffers from allergies and it affects her in multiple rooms of her house, so she needs an air purifier in each room. If your allergies are agitated in the space where you spend most of your time, you might get away with just having one unit in that room. |
As you can see, the number of air purifiers you will need in your home isn’t a straight answer. It comes down to these key variables that reflect your situation.
As well as the factors mentioned above, there are a few more things to consider before deciding if you need an air purifier in every room.
👂 Are you sensitive to noise?
Every air purifier creates noise as its fan spins around to circulate air. Not all units produce the same sound level — it can range from between 20dB up to 60dB+, depending on the model.
If you prefer a quiet household or don’t wish to be disturbed by the sound of electrical devices making noise, you might want to consider only having one unit, as more units = more noise. Be sure to look at our list of the quietest air purifiers on the market.
🌪 Does your home have good air circulation?
One of the reasons you might need an air purifier is poor air circulation in your home. A purifier will use its fan to push clean air into your space while removing harmful pollution that isn’t being circulated in your environment.
This could be due to a lack of ventilation or the shape of your room(s). If this is the case, your home may benefit from multiple air purifiers concentrating on areas affected by poor air circulation.
💰 How much $$ do you have to spend?
I’ve added this for the obvious reason; if you don’t have the budget to purchase multiple units…don’t.
But also, have you considered the extra costs that come with owning an air purifier? Air purifiers use electricity to run, and the amount of energy they use differs between models. This will affect how big or small your electricity bill will be.
📖 Case Study Smart Air’s Blast Mini (435 CFM) can use up to 122 watts on full due to its high-powered fan, while their smaller unit, the Smart Air S (185 CFM), pulls up to 42.6 watts. |
As HEPA filters trap airborne pollutants, they become full and less effective over time, reducing the total airflow. This means they need to be replaced periodically, and every model has varying filter lifespans and replacement costs. You can clean a HEPA filter with a vacuum but never use water as this will damage it.
Frequently Asked Questions About Air Purifiers
🤔 Will a single air purifier clean multiple rooms?
If you’re not in the position to be adding more air purifiers to your home, you can get a lot out of a single unit if you use it correctly.
We’ve got two tips and tricks to get the most out of your air purifier.
- Run Your Air Purifier Continuously
Most air purifiers are designed to run continuously throughout the day and night as long as you adjust the fan speed accordingly. Units don’t need to be set to maximum fan speed for extended periods; this is just a waste of energy and can be dangerous. Keep your purifier on a lower fan speed and turn it up when you need that boost (when cooking, when people are in the room, cleaning etc.)
- Move Your Air Purifier Around
Most units are designed to be moved around; some even come with wheels and handles to make it easier. Take your unit around your home with you. Before you sleep, place it in your bedroom to ensure clean air throughout the night, move it into the kitchen when you’re cooking, or run it in the living room when you’re chilling out after a day.
It needs to be a high-performing unit to get the most out of one air purifier. Here are our top three recommended air purifiers for the whole house.
🤔 Where should you place your air purifier?
Where you place your air purifier can make a big difference in how it performs. You should follow certain dos and don’ts to maximize your unit’s efficiency.
🚪 Find a spot as close as possible to as many doorways as possible to increase the amount of air circulating through the room that can be purified. But be sure not to obstruct foot traffic.
🛋️ Keep your air purifier clear of objects that might impede its efficiency. It won’t do a great job behind the sofa, under your bed or in the corner of your room.
👟 If there’s a primary source of pollution you’re aware of, place your air purifier near to it. This could be anywhere from where you keep your shoes, the basement, the bathroom, to where the dog sleeps.
🧭 Keep your unit as close to the center of the room as possible, again, without blocking foot traffic. The middle of the room is where most air passes through, so your air purifier will capture most contaminants here.

Final Thoughts
Running an air purifier in your home provides many health benefits, like keeping the air you breathe clear of harmful pollutants and VOCs. When researching which air purifier is best for your home, you will notice many differences between the specifications of different models.
You must get the right unit to fit your space, so measure up first and determine what you need from that air purifier.
We can’t tell you exactly how many air purifiers you’ll need for your home, as all needs are different. Hopefully, these tips will guide you, providing insight into what to look for when deciding if you need an air purifier in every room.
Last update on 2023-06-08 / Affiliate links / Images from Amazon Product Advertising API