Teddy Bear you got to get out of your world one of these days. Fresh air and humidity control are just a small part of the IAQ equation. And CO2 isn't the only measuring stick for IAQ. You ever hear of TVOCs, mycotoxins, endotoxins, mold spores, Radon, dust mites, outdoor ozone and pollen to name a few. Some areas of the country have to limit the fresh air into a building for many reasons. You must have that paragraph on auto redial. You got anything new and refreshing to post.