Graphic of air purifier vs houseplant

Over the years, there’s been a lot of debate about mechanical air filtration versus natural air filtration.

In particular, people have argued if houseplants can compete with air purifiers for cleaning your indoor air.

What spurred this debate was a 1989 study published by NASA that showcased the powerful air purifying capabilities of plants.

That study raised a few solid questions.

Are indoor plants enough to clean the air inside your home? Can an air purifier really purify the air better than a plant? Or are air purifiers just hype?

In this post, we’ll tackle these questions and give you an honest answer to the air purifier vs houseplants debate.

We’ll first start by explaining how does a air purifier work to clean the air, then move onto plants, and end with a few tips on how to choose the best option for your own home.

How Air Purifiers Purify the Air

There are four basic types of air purifiers available. Each one works to purify the air indoors but in slightly different ways.

1) HEPA Filter: An air purifier that uses a HEPA filter cycles your home’s air through a dense filter that’s located inside the machine. Filters labeled as “True-HEPA” are by far the best type, and can remove 99.97% of contaminants down to 0.3 microns in size that pass through it. This includes particles such as mold, dust, pollen, and pet dander.

Related Post: Best HEPA air purifier for allergies

2) Activated Carbon Filter: An air purifier that has an Activated Carbon filter is specialized to remove airborne odors and volatile organic compounds (VOCs). It catches odor-causing particles such as cigarette smoke, cooking odors, and pet smells, as well as vapors from cleaning agents, chemicals, and paints.

Related Post: Best air purifier for chemicals

3) UV Filtering: A UV filtering air purifier uses ultra violet light to destroy bacteria and viruses in your home’s air. It uses non-lethal radiation to break bacteria and viruses apart at the molecular level that pass through the machine.

Related Post: Best air purifier for bacteria and viruses

4) Ionic Generation: An ionic air purifier doesn’t use a physical filter to trap indoor pollutants but rather sends ions out into the air to attach to any floating contaminants. When the ions attach, the particles get too heavy to stay in the air and fall onto the ground. You then have to vacuum them up to fully get rid of them. Some ionizers do include a collection plate to attract the falling particles but it doesn’t collect them all, as explained in our article on how do ionic air purifiers work.

Related Post: Best ionizer air purifier

See all of Amazon's Best Selling Air Purifiers

How Plants Clean the Air

Now that you know about the different types of air purifiers, we’ll now answer the question “How do plants clean the air?”

Houseplants work primarily by absorbing carbon dioxide (CO2) from the air through their leaves. CO2 is then combined with water and sunlight to make carbohydrates that plants use to survive. During this process, known as photosynthesis, oxygen (O2) is released back into the air for humans and animals to breathe.

Additionally, plants also absorb many other gases in addition to CO2, including volatile organic compounds (VOCs) such as acetone, benzene, and formaldehyde. In 1989, NASA performed a study on indoor air pollution abatement that verified how effective plants were at cleaning the air.

VOCs can get into your home through a variety of ways including household cleaning products, paints, furniture, building materials, cosmetics, and hundreds of other sources.

As you can see, indoor plants are a natural type of filter and can purify the air of harmful contaminants. It’s no wonder why the air purifier vs indoor plants debate is such a hot topic.

Unfortunately, plants can’t absorb all forms of air pollution. Solid particles like dust, allergens, smoke, mold spores, and pet dander simply land on the plant’s surface and surrounding soil. If you’ve ever seen a dusty houseplant before, now you know why that happens.

While all plants purify the air to some level, there are some indoor plants are particularly better at it. The 1989 NASA study discovered that these plants were the best for air purification:

  • English Ivy (Hedera helix)
  • Janet Craig (Dracaena fragrans)
  • Golden Pothos (Epipremnum aureum)
  • Peace Lilly (Spathiphyllum)
  • Warneckii (Dracaena Warneckii)
  • Marginata (Dracaena marginata)
  • Mother-in-Law’s Tongue (Sansevieria trifasciata)

If you’re familiar with plants, you may notice that these varieties are larger, and many are trailing Ivy plants. The larger surface area a plant has, the more contaminants it can absorb from the air.

One thing you should be aware of is that overwatered plants can make the air quality in your home worse by producing mold. Mold and mildew are types of fungus that thrive in moist, warm areas that can be found inside a plant’s soil.

So if you do want to have a house full of plants, but don’t want to risk exposure to mold, then keep your plants on a good watering schedule. Additionally, you can get the best air purifier for mold and mildew to remove mold spores from the air for extra peace of mind.

How Many Plants Do You Need to Purify Air?

Although it’s not possible to answer the question “How many plants do I need to purify air?” in exact terms, you can follow a rule of thumb set by the NASA study.

The recommendation is to use 15 to 18 plants that have a container diameter ranging from 6 to 8 inches for a 1,800 square foot home.

To break it down into smaller terms, this works out to roughly one plant for every 100 square feet of floor space.

To find out the square footage of a room, all you have to do is multiply the width (in feet) by the length (in feet). For example, if your bedroom is 12 feet by 15 feet, the math would be:

12 x 15 = 180 square feet

For a 180 square feet bedroom, you would need at least two large houseplants for the best air purification.

Which Should You Choose: Air Purifier or Indoor Plant?

Now that you know how air purifiers and plants purify the air, you may not know exactly which side you should lean in the air purifier vs plants debate.

Here are a few tips to help you decide, do I need an air purifier or do I need indoor plants?

An Air Purifier is Better for:

  • People who don’t mind using mechanical air filtration
  • People with mild to severe allergies or asthma
  • People who want to remove the largest variety of contaminants from the air (i.e. dust, allergens, bacteria, mold, pet dander, smoke, etc.)
  • Homes that contain lots of dust or pet dander
  • Homes that don’t have a lot of extra room space to accommodate a number of plants
  • People who aren’t good at keeping plants alive and healthy

Here’s a page with our air purifier reviews which includes the top features pointed out for each one.

Houseplants are Better for:

  • People who prefer natural air purification
  • Homes that tend to have higher levels of VOCs (i.e. new construction or renovations, new furniture, an abundance of cleaning product use, etc.)
  • Homes that don’t accumulate much dust or pet dander
  • Homes that enough room space to accommodate multiple plants
  • People who are good at growing and maintaining houseplants
  • People who take extra steps necessary to keep their homes free of toxic pollutants (i.e. green living)

We hope this guide has helped you make a well-informed decision when it comes to an air purifier vs houseplants. Regardless of the direction you choose to go, the air quality in your home will be much cleaner because of it.

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About David Morrison

David is an Air Quality & Comfort Technician. He has expert knowledge on the technology and design of air purification, air conditioning, and heating systems. His main role is to write content that helps people get the most value out of their air purifiers, air conditioners, and heating units. (See Full Bio)