Indoor Air Filtration with Plants
As I’ve been learning about passive solar retrofits, I’ve also learned that when a home is better insulated, while it can make the energy systems more efficient, the quality of the indoor air can become more of a concern.
For example, when drafty windows are replaced, the home can become more energy efficient, yet an unintended result could be that the gas forced air heater that is in use for the winter needs the extra air from the leaky windows to function. As a result of creating a tighter envelope for the house, the air within the home can become polluted with gas and can potentially cause sickness – or in the worse case scenario, it could blow up.
In general, any time energy is used to heat or cool a space, the better insulated the environment is, the more efficient it tends to be. For example, less energy is needed to warm or heat a space if heat or coolness is constantly escaping. Indoor air pollution, however, can become an issue.
I recently came upon a post that discussed a situation in India where the indoor pollution became bad enough that people started to get sick. After doing research, they found that the utilization of three different plants worked as an effective form of indoor air filtration. Here is a short video of Kamal Meattle discussing about these plants.
In an effort to purify the quality of the air in their work environment, a company in India came up with three plants to “grow” fresh air. They are the:
- Areca Palm (Chrysalidocarpus lutescens)
- Mother-in-law’s Tongue (Sansevieria trifasciata)
- Money Plant (Epipremnum Anreum)
The end result was that productivity went up and the air was cleaner.
Similar to passive solar as the aikido of building design, with a little planning, choosing the right plants (and keeping them alive) will, by their inherent nature, passively and naturally filter the air.
***If you are considering doing an energy retrofit, make sure to consult a professional to ensure that your energy retrofit is safe. Older homes tend to have older appliances that utilize natural gas and may need airflow in order to function correctly. In this type of situation, simply filling a home with plants may not adequately deal with the amount of gas produced from a malfunctioning natural gas heater. Be safe!
Ventilation is required in all homes but especially in airtight insulation homes. We use a mechanical ventilation heat recovery system which retains heat but distributes fresh air throughout the house. Very comfortable and healthy. No condensation or mould growth
Hi Keya, I am learning so much about passive homes from your articles. Thank you!
My hubby and I are planning to convert a farmhouse from the 1800s into our permanent home, not far from Berlin. We are trying to incorporate as much passive house principles as we can, without going into debt, of course.
Two areas that we are still trying to decide are 1. the sloping of the glass in the sunroom along the south-facing side of the house. We’re trying to determine whether vertical or sloped glazing would be better and whether to have one story or two-story glazed surface.
And 2. indoor planters along the entire southern glazing to improve air quality and to bring a bit of outdoors into our home year round. Have you seen either of these in any of the projects you have visited and if so, have you heard any concerns or issues from owners regarding humidity/moisture control from plants/build-in planters, decrease in heat absorption to concrete floors (we’re planning to add polished concrete floors to the entire first floor), too much heat in summer from two-story glazed openings, or any other concerns that may not be apparent to a novice like us. Thanks again for the information material your provide.
It’s exciting that you’re in the process of planning a build. I’ll try to point you to other articles that might be able to steer you toward a decision. In talking to owner/builders, it seems that any type of sloping glass is especially vulnerable to leaks. I’m in a mountain state, so storms tend to be more harsh, but it may not be a concern in your area. Here are some links that may be of interest.
Earthships in Taos use sloping glass, tend to have leaks, and often have a greenhouse area in the southern facing side. This can raise the humidity levels inside the home.
Here’s a modified Earthship-style home that used vertical glass.
This home also has a greenhouse in the southern-facing front, but the growing space is much smaller, oriented on a south-north axis instead of east-west.
There are many homes that have two stories of glass on the south, and it seems to be that the amount of glass doesn’t necessarily mean that the home will be warmer or cooler, (while it is an important part of the factor) rather, it seems that the temperature is more effectively controlled by the length of the overhang. A link mentioned above for the Earthship style home – their owners said that they wished that they had made the overhang a little shallower because on certain days in the spring and fall, the home could use a little more solar heat.
The amount of solar heat that can be stored in the home also depends on the amount of thermal mass used, as well as the orientation of the home. This impressively efficient home has two stories of windows and is cool in the summer and warm in the winter because of the efficient use of thermal mass.
I’m not sure if you mean that you’re planning on having a greenhouse with dirt, or potted plants, but it is important to remember that concrete is hydrophilic and absorbs water.
I’ve seen demonstrations of artistic desiccant devices (that pull humidity out of the air with a high salt content) and while they look cool, I’m not sure if they work. There’s a close-up image of it in the gallery near the bottom of the post.
I’d recommend that you get some stats on your local climate for humidity, as well as cooling and heating degree days to make modifications to make an optimal design.
Let us know how it goes! Good luck!