Ventilator for beneath enclosed structures

An apparatus for ventilating the crawl space of a structure, comprising:

• at least one means for causing the transport of crawl space air, said air transport means adapted to, upon receiving an appropriate stimulus, cause the transport of crawl space air through an aperture in the structure to outside the structure;
• at least one humidity sensing means for determining the relative humidity of crawl space air and of outside air, respectively, and for transmitting respective stimulus dependent thereon (the "RH stimulus");
• at least one temperature sensing means for sensing the respective temperature of crawl space air and of outside air, respectively, and for transmitting respective stimulus dependent thereon;
• at least one control means including means for setting and storing at least one pre-set minimum absolute moisture differential parameter for ventilation activation, said control means functionally connected to said humidity sensing means for controlling the activation thereof and receiving RH stimulus therefrom, said control means also functionally connected to said temperature sensing means for controlling the activation thereof and receiving temperature stimulus therefrom, said control means also for determining therefrom the respective absolute moisture of the crawl space air and of the outside air and for determining the absolute moisture differential therebetween and comparing said differential to said minimum absolute moisture differential parameter for ventilation activation, said control means also functionally connected to said air transport means for controlling the activation thereof.