air purifier on hardwood floor with houseplant in room

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How Do Air Purifiers Work?

Simply put, an air purifier is designed to take the dusty air and turn it into air that is clean and healthy for you to breathe. Each air purifier has a Clean Air Delivery Rate (CADR Rating) and Air Changes Per Hour (ACH Rating) which measure it’s effiency. Keeping those ratings high ensures that your machine is doing its job.

Inside the best home air purifier units, you’ll find an electric fan that draws air into the unit and then forces the dirty air toward a filtration system as a way to clean it. There are two main layers of this filtration system that this air will pass through. The first filter layer that the dust hits contains a larger more coarse material that traps the bigger dust particles, called a pre-filter air filter. Anything that is small enough to slip through this pre-filter goes to the second part of the system, the HEPA filter.

HEPA stands for High-Efficiency Particulate Air, and this is a very dense layer of material that traps even tiny dust particles and keeps them out of the air you breathe. An air purifier with a HEPA filter can filter out and trap up to 99.97% of dust particles. To keep your air purifier operating at peak performance you’ll need to change or clean these filters regularly.

Tips For Using Air Purifiers in Large Rooms

To get the most value out of your purchase, there are a few simple tips you can follow.

  • Location, location, location: The closer the air purifier is to the room center, with at least 24 inches away from the wall, the more it can draw air in from every corner and circulate it through the filters. Obstructing its airflow by being behind furniture or tucked into a corner of the room can decrease efficiency by 50% or more.
  • Place it 3 to 5 feet off the ground: Putting the air purifier on a table or mounting it on the wall will allow the unit to better filter horizontal indoor air movement as well as vertical air movement.
  • Keep it running: Air purifiers run at peak performance when they operate 24 hours, 7 days per week. If the cost of running your air purifier all day worries you, rest assured that these machines are very energy efficient and barely impact your electric bill.
  • Do not place it in a room with high humidity: High humidity means heavier air and this can decrease the efficiency of the air purifier, especially in large rooms. Higher humidity will reduce the capacity of filters (especially HEPA filters) by making them damp. This will also make the unit use more energy.
  • Keep windows and doors closed: Try to keep the air purifier inside a tightly closed space to give it a chance to fully exchange the air inside. Each time the seal is broken, clean air escapes and contaminants enter, which makes the air purifier work harder to keep the air clean.
  • Check and change filters regularly: A full filter can’t do anything for air quality. Some of the best purifiers include an indicator that alerts you for when it’s time to check or change the filters. The easiest rules of thumb for changing are if the True HEPA filter looks brown and dirty and if the Activated Carbon filter is coated in white dust. 

What to Look For in Air Purifiers

True HEPA Filter

Essential in a basement air purifier because it’s the only type of HEPA filter that’s certified to capture particles as small as 0.3 microns. This includes mold spores, dust, allergens, smoke, pet dander, and thousands of other particles. However, watch out for air purifiers that use the words “HEPA-like,” “HEPA-type,” or just “HEPA” when referring to the filter. If it doesn’t have the word “True” attached to it, then it’s an inferior filter that won’t be the best HEPA air purifier for allergies and other particles in your basement.

Activated Carbon Filter

Another must-have feature because it’s the only type that can reduce odor and volatile chemical compounds. An activated carbon air filter does this through a chemical process called “adsorption,” where odor particles cling to the filter medium. Activated carbon is the only substance that can remove a musty smell and volatile organic compounds released from appliances, cleaning solutions or even just building materials.


If you don’t get the right size air purifier for your space, you won’t be reaping all the benefits. Many models and brands may even offer different sizes for different size spaces – and the math is easy to do. Measure the width and lenth (in feet) of your basement, or room, and round up to the whole number. Multiplying the width and length will get you the square footage of the space. This is especially important in a large space where you either need a properly equipped air purifier, or sometimes even two in one space.

ImageAir Purifier DetailsPrice
RabbitAir MinusA2 Ultra Quiet
  • Best overall Purifier
  • Filter: HEPA Air filter
  • Coverage: 815 sq. ft.
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Alen BreatheSmart
  • Runner Up
  • Filter: H13 True HEPA
  • Coverage: 700 sq. ft.
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Medify MA-40 Air Purifier
  • Runner Up
  • Filter: HEPA H13 Filters
  • Coverage: 840 sq. ft.
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Molekule Air Pro
  • Runner Up
  • Filter: PECO-Filter
  • Coverage: 1000 sq. ft.
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IQAir HealthPro Plus Air Purifier
  • Runner Up
  • Filter: HyperHEPA
  • Coverage: 1125 sq. ft.
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Coway Airmega 300S App-Enabled
  • Runner Up
  • Filter: Pre-Filter + True HEPA
  • Coverage: 1256 sq. ft.
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Austin Air HealthMate
  • Runner Up
  • Filter: Medical HEPA Filter
  • Coverage: 780 cubic inch
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The Best Air Purifiers for Large Rooms

If you have a room that’s not too overly large, then this Rabbit Air MinusA2 air purifier is a great option, as it covers 700 to 815 square feet. It comes in three different models depending on the amount of coverage you need.

What makes this air purifier a great buy is that it offers unmatched air cleaning performance. It strips practically every harmful particle from the air. If you have allergies, asthma, or other sensitivities, it can reduce the contaminants that irritate you the mos This air purifier also excellent for filtering out tobacco smoke and its odors as well as volatile organic compounds (VOCs).

The six-stage air purification process includes:

  1. Pre-filter: Traps the largest particles and extends the life of the other internal filters.
  2. Medium Filter: Traps large allergens and dust.
  3. BioGS HEPA Filter: Collects 99.97% of pollutants down to 0.3 microns. Specially designed True HEPA filter that lasts up to 3 years.
  4. Activated Carbon Filter: Traps odors and VOCs.
  5. Customized Filter: Let’s you tweak the air purifier to suit your specific needs. Choose between Enhanced Germ Defense, Toxin Absorption, Pet Allergens, or Odor Elimination.
  6. Ion Generator: Adds an extra boost of air cleaning power.

Two additional features you’ll enjoy are:

  • It can be wall-mounted.
  • The front panel comes in two different colors and numerous designs. It can blend in as a piece of art in your room.
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This air purifier that gives you the flexibility to customize the internal HEPA filter and choose a front panel design that meets your individual needs. It covers up to 1,100 square feet.

This Alen BreatheSmart air purifier gives you a choice between four types of True HEPA filters:

  • HEPA-Pure: Targets microscopic allergens.
  • HEPA-Silver: Includes an extra layer of protection for asthma sufferers.
  • HEPA-FreshPlus: Includes extra layers to attack smoke and heavy chemical vapors.
  • HEPA-OdorCell: Includes extra layers to combat strong odors from pets and babies.

This model also includes an air cleaning boosting ionizer.

As for color choices, the front panel comes in 14 different colors and designs. You can choose between white, blue, brown, pink, graphite, champagne, brushed bronze, brushed stainless, black, rosewood, natural maple, and more.

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What makes this product so good is the 4-Stage Air Cleaning System with one of the highest grade HEPA filters available, and covers up to 840 square feet. This powerful air purifier tackles pollutants of all types—making the room it’s placed in a much healthier environment.

The 4-stage air cleaning system includes:

  • Pre-filter: For trapping the largest particles and extending the life of the other air filters.
  • Medical Grade H13 HEPA Filter: A higher grade filter than a standard True HEPA filter. It captures 99.95% of microscopic allergens, dust, and mold spores down to 0.1 microns in size. An excellent choice for people who suffer from allergies or asthma.
  • Activated Carbon Filter: Reduces odors and gases caused by pets, smoke, cooking, paint, and new building materials so the room smells fresh.
  • Ionizer: Produces negative ions to improve the efficiency of the internal air filters and revitalizes the air.

While this particular air purifier is made for large rooms up to 840 square feet, there’s also a smaller model available: The Medify MA-25, which is good for spaces up to 500 sq. ft.

Two other things worth pointing out is that this air purifier also comes with a 8-hour Timer and Child Lock. The timer lets you set the air purifier to automatically turn off after 0-8 hours when don’t need it running all day. And the child lock disables the control panel buttons so that the settings can’t be changed.

It’s also one of the only air purifiers with a Tempered Glass Panel so you never have to worry about it getting scratched like plastic other plastic models.

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How would you like an air purifier that actually destroys and not just traps airborne pollutants at a molecular level?

If you want a unit that can eliminate all traces of particles in your home, then you’ll want to consider this air purifier right here.

It’s the only one that uses advanced PECO filtration technology:

  • PECO filtering doesn’t just trap particles on a filter as HEPA air purifiers do. Instead, PECO destroys airborne contaminants at their core so they vanish from existence.
  • PECO nanotechnology destroys allergens, mold, bacteria, and viruses so you have the cleanest, healthiest air to breathe.

As for controlling this air purifier, you have two choices:

  • The touch screen display on the top of the unit allows you to make adjustments to the fan speeds and automatic modes.
  • The Wi-Fi app lets you sync it up with your iPhone or Android device for full wireless control.

One of the most stylish air purifiers you’ll find today for your home, it covers up to 600 square feet.

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Covers 1,125 square feet

This medical-grade air purifier can handle an extra large room inside your home or office.

While it’s marketed for people who have severe asthma or allergies, it’s also excellent for anyone who wants the cleanest, freshest air possible in a large space.

The two features that stand out include:

  • Advanced HyperHEPA Filter – Captures 99.95% of particles down to 0.003 microns—the smallest that exists. It also lasts up to four years.
  • V-5 Gas and Odor Filter – Captures toxic gases and odors from volatile organic compounds (VOCs), automobile exhaust, paints, carpeting, furniture, formaldehyde, and carbon monoxide. It lasts up to two years.

The super long-lasting filters make this a great, lower maintenance pick.

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Wi-Fi capabilities let you control the unit from your mobile device and get real-time reports and updates about the quality of your indoor air.

This model comes in two versions to cover some of the largest spaces possible:

  • 300S Model (covers 1,256 square feet)
  • 400S Model (covers 1,560 square feet)

To cover such a massive amount of space, this air purifier actually combines its internal filters into one Advanced Max2 Filter Set.

  • The True HEPA Filter removes 99.97% of pollutants down to 0.3 microns.
  • The Activated Carbon Filter captures 99% of volatile organic compounds (VOCs) and odor-producing particles.

This air purifier is fantastic for open floor plans, basements, office spaces, and other extra large room indoor areas.

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Covers 1,500 square feet

The Austin Air HealthMate is a simple, reliable, powerful device that doesn’t have any the other frills and drills, but does come in two color options. You turn it on, choose a speed setting, and enjoy freshly cleaned air.

The thing that makes it stand out from other air purifiers is that it offers 360-degree air filtration.

  • This unit draws air in through every side, not just the front like other brands.
  • This design maximizes airflow and offers less restrictive placement inside a room.

As for the internal air filters, you get a combination filter that includes:

  • True HEPA Filter: Captures 99.97% of contaminants down to 0.3 microns.
  • Activated Carbon Filter: Includes 15 lbs. of activated carbon which is unmatched in the marketplace. This machine is a beast for removing household odors, tobacco smoke, and volatile organic compounds (VOCs).

Best of all, the filter life expectancy is 5 years. So you can enjoy clean, fresh air without having to pay for a replacement for half a decade.

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Bottom Line

We hope this detailed guide on how to find the best air purifier for large spaces was helpful for you.

As you discovered, it’s very important for you to get the right size air purifier for your needs.

You can’t just place any size air purifier in a room and expect it to work well.

Small air purifiers are made for small rooms, large air purifiers are made for large rooms, and extra large air purifiers are made for extra large rooms.

By choosing any of the best large room air purifiers on this page, you can ensure that you’re getting a high-quality product that will keep the air around you fresh and clean.