The NASA did some research about house plants and found that some of them were efficient in removing CO2, producing oxygen and even removing COV's. They recommended using 16-20 plants per typical house in order to get clean air. For a tightly insulated house with low flows of outside air (mine is at 1.12 air exchange at 50 pascal), would you think that would give enough oxygen, remove enough CO2 and COV's to replace a part of HRV air exchange functions? Wouldn't it be a clean and energy efficient way to have "fresh" air in a modern typical bungalow? I know the humidity issue. But some efficient plants (like Sansevieria plants) can live very well with very infrequent watering and if you remove humidity at source with bathroom fans, kitchen fan, etc., one would need to use less his HRV in order to remove excess humidity in the builing...and you can monitor it so if it goes to high, you start the HRV. Last thing, I know plants can produce acarians, but if you have an air recirculation mode and a very efficient filter in it, that issue is solved. What do you think about this idea? Thank you very much!

Its a good idea to have plants in the home but it cannot replace mechanical ventilation. Code would not allow it. In a tight home with many occupants the plants could not remove enough carbon dioxide. Get an ERV and keep the plants. Both will work together to provide clean and fresh air.

I already have a heat recovery ventilator with a HEPA filter. It provides the house with 80-110 cfm of fresh and filtered air. Anyway, that's a general question. Not everybody have whole house mecanical ventilation with a high efficiency filter included. But I would guess that a house with 15-20 well selected house plants (low water needs, high oxygen production) would still improve the air quality of the home. I'm not just sure about what would be the rate of CO2 removal by them and how many would be needed in order to give the equivalent of 15 (cfm 1 occupant), 30 cfm (2), 45 cfm (3), 60 cfm (4), cfm of fresh air. Any tought on this?

By the way, somebody at University of Sydney did a research on indoor plants CO2 and CO reduction effects in offices, noting that no previous researchs was done about it. The resultats are very interesting. See the end of the report. In one case, CO2 levels were below those you will see outside (290 ppm inside vs. 350-400 ppm outside).

http://greenplantsforgreenbuildings.org/attachments/contentmanagers/25/PlantsCleanseIndoorAir.pdf