Air-purifying plants are on almost every list of house plants you "must have", often with the promise that they filter harmful substances from the air and make your home healthier. That claim is based on real research, but the story has been greatly exaggerated over the years. A snake plant in the corner is no substitute for an open window, and ten plants on the windowsill won't turn your living room into a fresh mountain meadow.
Still, there are plenty of reasons to bring plants into your home. In this blog, you'll learn where the idea of air-purifying house plants comes from, what they can and cannot do in an ordinary home, which varieties are the best choice and how to care for them so they stay healthy.
Where does the idea of air-purifying plants come from?
The name air-purifying plant is largely thanks to NASA. In the late 1980s, environmental scientist Bill Wolverton investigated for NASA whether plants could keep the air clean in enclosed spaces, such as a space station. In small, airtight test chambers, a plant was placed together with a substance such as formaldehyde, benzene or trichloroethylene. After a day and night, the concentration of those substances had clearly decreased. The 1989 report listed a number of common house plants, including the peace lily, spider plant, ivy and several varieties of Dracaena.
One striking result received less attention at the time: a large part of the work was not done by the leaves, but by the microorganisms around the roots and in the potting soil. In addition, these were small, completely enclosed chambers, without ventilation and without any new supply of pollutants. That is a very different situation from a living room with a door, windows and ventilation grilles.
What air-purifying house plants really do in your home
In 2019, two American researchers from Drexel University compared the results of dozens of plant studies and calculated what they would do in a real home. Their conclusion was down-to-earth: to match the effect of ordinary ventilation, you would need somewhere between 10 and 1,000 plants per square metre. In a normal home, the air is ventilated many times a day through gaps, grilles and open windows, and that does much more than a few pots on the windowsill.
Does that mean plants do nothing? No. They do absorb small amounts of substances, they evaporate water which makes the air slightly less dry, and there is a lot of research showing that people feel more comfortable, calmer and more focused in a space with greenery. If you really want to improve the air, start by ventilating, and then choose plants because they make a room more beautiful and pleasant.
The best air-purifying house plants
The varieties listed below all appear in the NASA research or in later research into plants and indoor air, and they are also hardy enough to stay in your home for years. You will find many of these plants in our collection of air-purifying plants.
Spathiphyllum (peace lily)
The peace lily scored well on several substances at the same time in the NASA research and has since become the prime example of an air-purifying plant. It has large, soft leaves that evaporate a lot of water, and it blooms with white spathes. It clearly shows when it is thirsty: the leaves droop and quickly stand up again after watering.
Chlorophytum comosum (spider plant)
The spider plant grows quickly, produces long runners with small plants on them and is virtually indestructible. Because it produces a lot of foliage in a short time, it is a great plant to group together, for example on a shelf or in a hanging basket. Moreover, it is not toxic to cats and dogs.
Sansevieria (snake plant)
The snake plant is a special case. It belongs to the plants with so-called CAM photosynthesis: to conserve water, it opens its stomata mainly at night and takes in some of its carbon dioxide then. This has given it the reputation of being the ideal bedroom plant. Its effect on the air in a bedroom is small, but as a strong, sleek plant that requires almost no water, it is an excellent choice.
Epipremnum aureum (scindapsus)
The scindapsus is a fast-growing climbing and trailing plant with lots of leaves on long vines. It appears in several studies on indoor air and is very easy to care for. Place it high on a cabinet or let it grow along a plant stand. View the varieties in our collection of scindapsus.
Dracaena (dragon tree)
Several varieties of Dracaena were tested in the NASA research, including Dracaena marginata and Dracaena fragrans. With their stems and crowns of long leaves, they add height to a room without taking up much floor space. Discover our Dracaenas in various sizes.
Dypsis lutescens (golden palm)
The golden palm has lots of feathery leaves and therefore evaporates quite a bit of water. This means it can contribute a little to the humidity in a dry, heated room. It likes a bright spot without harsh afternoon sun and is safe for pets.
Ficus elastica (rubber plant)
The rubber plant has large, leathery leaves with a large surface area. It grows into a sturdy plant for a bright corner and is easy to care for, as long as it is not kept too wet.
Nephrolepis exaltata (sword fern)
The sword fern has fine, dense foliage and likes humid air. That is precisely why it is well suited to a bright bathroom, where it can benefit from the steam after a shower. It is not toxic to cats and dogs.
Hedera helix (ivy)
Ivy was on the original NASA list and is a good indoor hanging plant for a cool, bright spot. In a warm, dry room, it is more prone to spider mites. Note: ivy is toxic to humans and animals.
Comparison: which air-purifying plant is right for you?
All the varieties in this blog are good house plants, but they each have different requirements. Use this table to quickly see which plant is right for your space, watering routine and any pets.
| Plant | Light | Water | Growth | Safe for cats/dogs |
|---|---|---|---|---|
| Peace lily | Partial shade to light | Moderate to high | Moderate | No |
| Spider plant | Light, no harsh sun | Moderate | Fast | Yes |
| Snake plant | Shade to sun | Very little | Slow | No |
| Scindapsus | Partial shade to light | Moderate | Fast | No |
| Dracaena | Light, no harsh sun | Low | Slow | No |
| Golden palm | Light, no harsh sun | Moderate | Moderate | Yes |
| Rubber plant | Light | Low to moderate | Moderate | No |
| Sword fern | Partial shade | High, humid air | Moderate | Yes |
| Ivy | Light and cool | Moderate | Fast | No |
If you have a cat or dog, choose the spider plant, golden palm or sword fern, or explore our collection of pet-friendly plants. In our blog about house plants that are not toxic to cats and dogs, you can read which varieties are best kept out of reach.
How to get the most out of your plants
A healthy plant with lots of leaves and active roots evaporates more water and keeps the soil life in the pot active. A few simple habits will help you do this.
Choose the right spot
Light is the engine of every plant. A peace lily or scindapsus can survive in partial shade, but a rubber plant or golden palm really needs a bright spot, as does a Yucca (see our guide Caring for a Yucca). If you are unsure, read our guide on the right location for plants.
Keep the leaves dust-free
Dust on the leaves blocks light and reduces gas exchange through the stomata. Wipe large leaves once a month with a damp cloth, or place smaller plants under a lukewarm shower.
Water at the right time
Overwatering is the main cause of sick plants in the home. Wet soil without air suffocates the roots and the beneficial soil life. First feel with your finger whether the top few centimetres are dry; you can find more information on our page about watering. A pot with drainage also helps, as we explain in the blog about why drainage is important.
Do more for clean indoor air
Because plants only refresh the air to a limited extent, these measures are at least as important. Especially in autumn and winter, when windows remain closed and the heating is on.
- Ventilate every day. Always leave ventilation grilles open and ventilate thoroughly after cooking, showering and sleeping.
- Use the extractor hood. Gas cooking and baking release a lot of fine particles and moisture.
- Limit scented candles and sprays. They add substances to the indoor air.
- Let new furniture and paint air out first. This is when most volatile substances are released.
Air-purifying plants for each room
For the living room, choose plants with lots of foliage and a large size, such as a rubber plant, golden palm or tall Dracaena. For a stately centrepiece, find more ideas in our overview of the most beautiful large house plants. In the bedroom, calm, hardy plants like the snake plant or peace lily are suitable. If it is dark there, look at our tips on house plants for low light.
In the bathroom, plants that like humid air do well, such as the sword fern. At a workplace or in the kitchen, a spider plant or scindapsus is convenient: they grow quickly and forgive you if you forget to water them once in a while. If you have just started with plants, also read our blog about easy house plants.
Frequently asked questions about air-purifying plants
1. Do house plants really purify the air?
Plants absorb small amounts of substances, and the soil life in the potting soil also breaks down substances. However, in an ordinary home, this effect is small compared to ventilation. Therefore, think of plants as a supplement to a healthy indoor climate, not as a substitute for an open window.
2. Which plant purifies the air best?
In the well-known NASA research, the peace lily, spider plant, ivy and several varieties of Dracaena scored well. In practice, the variety matters less than the health of the plant: a large, healthy plant with lots of foliage does more than a struggling plant.
3. How many plants do you need for clean air?
According to a review study from 2019, you would need between 10 and 1,000 plants per square metre to achieve the same effect as ordinary ventilation. This is not feasible in a home. So choose as many plants as you like and can care for well, and continue to ventilate.
4. Is a snake plant good for the bedroom?
Yes, the snake plant is an excellent bedroom plant. It takes in some of its carbon dioxide at night, needs little light and water and remains compact. Do keep it out of reach of cats and dogs, though, because it is slightly toxic.
5. Do house plants increase humidity?
Plants evaporate water through their leaves and thus contribute a little to the humidity. Varieties with lots of foliage, such as the golden palm and peace lily, do this the most. A group of plants together has more effect than individual plants scattered throughout the home.
6. Which air-purifying plants are safe for pets?
The spider plant, golden palm and sword fern are not toxic to cats and dogs. The peace lily, snake plant, scindapsus, Dracaena, rubber plant and ivy are; it is better to place them in a spot where your pet cannot reach them.
