Indoor plants that clean the air: fact or fiction? | Blog | Unovent

Indoor plants that clean the air: fact or fiction?

18 July 2019
Indoor plants that clean the air: fact or fiction? Indoor plants that clean the air: fact or fiction? Blog

It’s appealing to think that house plants can do double duty - looking gorgeous and also cleaning the air in your home.

House plants were hugely popular in the 1970s and 80s, and now they’re making a big comeback. Garden centres throughout New Zealand have an ever-expanding range of indoor plants and some of them claim to be ‘air purifying plants’ that clean the air in your home. Does science support this concept? Maybe…

Plants are able to absorb gases through pores on the surface of their leaves. It's this ability that makes photosynthesis possible. Harking back to your high school bio class, photosynthesis is the process by which plants convert light energy and carbon dioxide into chemical energy for growth.

But (and it’s a big but) you’d need a veritable jungle of air purifying indoor plants in your home to make any positive difference to air quality. And the microbes and moisture introduced into your home by that jungle would not be particularly good for your health.

The problem with the ‘air cleaning’ myth is that it’s based on a 1989 NASA study that was looking for ways to clean air in space stations. This NASA study showed that plants could clean air in a closed, limited environment or chamber. Other studies have also found that plants can absorb other gases in addition to CO2, including things like benzene (found in plastics and and cigarette smoke) and formaldehyde (found in various cleaning and cosmetic products).

However if you were to scale-up NASA’s experiment, you’d need hundreds of air filtering plants inside your house. A reviewer from the U.S. Environmental Protection Agency said that achieving the pollutant rate reached in the NASA study would require having ‘680 plants in a typical house’. Interestingly, the drive to spread the ‘air cleaning plant’ myth appears to have come from a gardening industry organisation. Clearly, they had something to gain.

Another expert, Stanley Kays of the University of Georgia, says that air exchange between the interior and exterior of a home has a far great effect on indoor air quality that keeping house plants. So in truth, getting a home ventilation system like Unovent will always be the most efficient way to keep the air inside your home fresh and healthy.

Why fresh air exchange is important for your home

The Energywise NZ government website says “Good ventilation is essential for maintaining air quality and removing excess moisture from your home. Having a draughty house is not the same as having good ventilation. As houses get more airtight, they become easier to heat, but good ventilation is still important to stop inside air getting stale and damp.”

Getting a proper ventilation system for your home comes with many benefits:

  • Your home won’t smell stale and feel stuffy when it’s been locked up all day
  • Indoor air is less humid, which discourages microbial growth (mould, mildew and bacteria)
  • Dust mites are less likely to thrive, making your home healthier for family members with asthma
  • You won’t have to sleep with your windows open, which can be a security issue
  • In winter, your windows won’t be dripping with condensation

If you love house plants, go right ahead and get some

If you’ve been thinking of loading your home up with peace lilies, philodendrons, spider plants and monstera (some of the so-called ‘best indoor plants for air purification’), don’t let us stop you. But do it because you like the way they look, not because you think they’ll improve indoor air quality.

For a no-obligation quotation (over phone or email), call 0800 UNOVENT (0800 866 836) or email

Read more about how home ventilation can improve family health