Abstract: An automatically controlled forced air ventilating device for installation in a structural wall and used in controlling the movement of air into and out of a prescribed area. A ventilator apparatus for the device includes a first stationary plate and a second movable plate, each of the plates including apertures therein and a control means for moving the second plate between first and second positions in which the apertures are aligned and not aligned. A fan is attached to the ventilator apparatus for moving air therethrough at times when the second plate is in the second position with the apertures aligned. A sensing means senses prescribed conditions of air and activates the fan and the control means responsive thereto when prescribed levels of air conditions have been exceeded.

Abstract: An automatically controlled, responsively to minimum temperature and humidity levels, ventilation system for crawl spaces beneath a house or other structure includes at least one intake unit and one exhaust unit. The intake unit includes at least one solenoid-operated ventilator and a temperature sensing device positioned to sense the temperature of outside air. The exhaust unit includes at least one solenoid-operated ventilator, a fan, and a remote humidistat positioned to sense the humidity level at a prescribed area of the crawl space. When the humidity rises above a prescribed level, the humidistat closes an electrical circuit to the thermostat. If the outside air temperature is above a prescribed level (at least above freezing), the thermostat closes the second circuit, energizing the solenoids and the fan. The solenoids cause the ventilators to open and the fan forces air through the crawl space to reduce moisture levels and dissipate any build-up of Radon gases beneath the structure.