HERS IAQ testing will likely be part of a newly constructed home or addition when triggered by a performance approach CF1R .
IAQ New homes are being built that are much more air tight than past homes. This trend, while improving energy efficiency, has some unintended consequences like sick building syndrome. Many parts of a new home will off gas minute amounts of toxins that are only an issue if the house is not properly ventilated. A simple IAQ (exhaust) fan within the home slightly negatively pressurizes the house so fresh outside air is forced into the house through the few gaps that still exist. The CF1R will tell you how many IAQ CFMs are required for the home.