I was in a cab from the airport in Whitehorse, Yukon Territory, to my hotel and was talking with the driver. He had an indoor fresh vegetable grow operation attached to his house. He claimed he made good $$ providing fresh tomatoes and other stuff to local Whitehorse restaurants during the long, very severe, winter months.
He told me that his grow results increased dramatically after he installed an exhaust system from his house to the grow building. He lived with his wife, two kids and a couple of dogs. He maintained that the increase in CO2 made all the difference.
I remain a bit skeptical when hearing anecdotal stories, but this one sounded believable.
6 CO2(g) + 6 H2O + photons → C6H12O6(aq) + 6 O2(g)
carbon dioxide + water + light energy → glucose + oxygen