incoming air. If the door were left ajar, I could not be sure of proper flow rates for the element. Also, if you have, or are planning, a composting toilet, you do not want to reverse the natural ventilation that occurs in that type of fixture.

There is, in many homes, another major source of moisture. It is the automatic clothes dryer. Many people buy those totally useless plastic boxes that divert the warm exhaust air from the dryer back into the house. This air has a large amount of moisture and aside from creating the moisture problems addressed earlier, it also makes the dryer work longer. That is because the moisture it just got rid of is now being drawn right back into itself. Clothes should not be dried within the heated structure. A good place for the dryer is the garage or an unheated vented basement. The dryer, like the fireplace, needs a large amount of air to run properly.

The sale of dryer exhaust diverters is another piece of misinformed retailing that must cease. The deletion of water vapor as an important pollutant in chapter 3 is a grave error. It is a problem that must be addressed in any house-tightening program.