easy. The forced air furnace runs ductwork through the vented crawl space. I removed the bathroom branch and closed it off at the trunk. I installed a section of triple wall chimney pipe to the register. In this pipe I installed a small heating element and a blower fan. This takes air from the crawl space and blows it into the room. If the air happens to be uncomfortably cool the heating element can be turned on. When the switch that turns on the heat is used, it over rides the speed control on the fan to insure an adequate flow of air over the element for safe operation. The heating element also has an over heat protection thermostat.

For added heat in the bathroom, a double set of heat lamps are in the ceiling. The air blower/heater is controlled by a 60-minute spring timer. This way the system can be left on to work after the person has left, and not accidentally run all day.

The air being blown into the room displaces moisture-laden air through a short, but wide window near the ceiling (see item C Fig. 6). The windows shape will not allow access to intruders, so it can be left open any time. Most bathroom fans have a capacity or 40 to 80 c.f.m. This is insufficient to the task. I recommend a blower capable of 200 to 500 c.f.m. This size of blower tends to be loud. That is why I install a speed control. While the room is occupied, the fan can be run slow and quiet. When the person leaves, the fan can be turned up and left to finish the job.

So there it is, a bathroom with its own H.V.A.C. system, separated from the rest of the house by a weather-stripped door. It is successful in stopping the migration of large volumes of moisture vapor into the rest of the house. I call the concept the "Inside-Out House".

The question sometimes comes up as to why I pressurize the bathroom rather than use an exhaust fan. First of all, I could not safely preheat the