Do Living Walls Really Contribute to Clean Air? Not In Chicago.
Image credit Ambius
UPDATE: I grossly overstate the power required to run the wall and have written a new post: Do Living Walls Really Contribute to Clean Air? Apparently, Yes.
It is such a pretty thing, the 720 square foot living wall in the lobby of the Chicago Embassy Suites. The GSky Plant System design has an energy efficient computer controlled irrigation system. Designer and Project Manager Denise Eichmann says "The living wall is planted with 3,840 plants which represent six species....This green wall provides clean oxygen indoors, equivalent to 16 fourteen-foot-tall trees."
But is it really contributing to a cleaner atmosphere overall?
image credit GSky
Looking at the specifications for the GSky Living wall, it appears that the controller draws about 220 watts of power. Assuming that it always is running, that is 5.333 kWh per day. Chicago's electricity supply is powered by coal, which produces 2.3 pounds of CO2 per kilowatt hour . So the electricity used to operate the living wall is produced at the cost of creating 12.26 pounds of CO2 per day.
Project Manager Eichmann says that the green wall "provides clean oxygen indoors, equivalent to 16 fourteen-foot-tall trees." It does this through photosynthesis, absorbing carbon dioxide. According to Colorado Trees, a healthy mature tree absorbs 48 pounds of CO2 per year, or .1315 pounds per day, so the sixteen tree equivalent means that they are sucking up 1.709 pounds of CO2 per day. So 7.17 times as much Carbon dioxide is created powering the thing as is absorbed by it.
Green walls are lovely things. They make the lobby comfortable and absorb noise and pollutants. But Hilton says "The Live wall is a strong visual statement demonstrating the support of Hilton Worldwides' commitment to green efforts with all of their brands."
But unless they are buying green power or put solar panels on the roof, there is no commitment to green. I wish people would stop promoting green walls as environmentally beneficial without a full life cycle analysis, and when a better solution for the environment would have been to simply plant 16 fourteen-foot-tall trees in their giant lobby and be done with it.