technique used in the desert to trap water vapor under a plastic sheet.

The attic vents must also remain open due to the migration of water vapor from the living space. In the tight construction of the "super insulated house" this migration will be minimal, but in the average retrofit dealt with in the B.P.A. program, a good ventilation system is the only way to prevent dry rot from growing in the rafters. There are also records of strong allergic reactions to the mold and mildew associated with dry rotting conditions.

With proper humidity control, condensation on windows should be no more than a slight fogging. If storm windows or double-glazing is added, the problem should all but disappear. It can only be concluded that humidity has a direct and distinct effect on the health and well being of the occupants and the structure itself.

MITIGATION BY ACTION OF WATER VAPOR. To solve a problem we must first identify it. The two major areas of concern are the kitchen and the bathroom. The kitchen is discussed in the section on natural gas stoves. Therefore, to avoid redundancy, I will turn to humidity control for the bathroom. (see Fig. 6)

The first requirement for dealing with water vapor is to trap it. This is very effectively done by the installation of weather-stripping on the bathroom door. Interior passage doors are notoriously leaky. Next, the room should be disconnected from any central H.V.A.C. system. The occupancy rate of a bathroom does not justify the maintenance of a constant temperature. Do not think me cruel, I like a comfortable bathroom. To this end I install a separate heating system. It can be turned on in one of two ways, by a preset timer, or by the occupant upon entering the room. The bathroom must be provided with its own separate air supply. In my own house this was very