Abstract: A thermoelectric heating and cooling system which includes a load plate, one or more thermoelectric devices and a heat sink. The load plate includes a housing having a hollow cavity filled with a fluid which changes temperature slower than the load plate housing to thereby act as a sustaining phase change reservoir to help maintain the desired temperature on the load plate. Each thermoelectric device is separated from the heat sink by a spacer formed of material having high thermal conductivity. The spacers, in conjunction with material having low thermal conductivity which separates the load plate from the heat sink, forms a spacer duct for the passage of fluid between the load plate and the heat sink and around the spacers. A housing surrounds the exterior surfacer of the heat sink to form a heat sink duct for channeling fluid across the fins provided on the heat sink. The heat sink duct and the spacer duct are interconnected, whereby a single fan can force fluid through both.