Well, I will read that link you supplied, but there is a little hick-up with this idea.

If your using gas burning appliances (Boiler, Furnace, Water Heater), they will be vented to the outside, and for good reason. If you circumvent the vent, you might be helping your plants, but you will be killing yourself.

While this might be a good idea for those who have mechanical rooms outside of their residence, and plan on doing something like you've described, for the other 95% with the mechanical rooms inside, I would highly recommend you do not try it.