"Coastal Northern California is blessed with a very moderate climate, generally on the cool side, especially at night. Before the refrigerator became common in households, denizens of this region took advantage of the cool weather by storing perishable foods in a special kitchen cabinet that brought in air from the outside - the California Cooler.
The cooler cabinets were designed to hold fruits, vegetables, and other staples that needed to be kept cool but didn’t need to take up critical space in the era’s tiny ice boxes. The coolers were open to the basement to draw in cool air, which then wafted up and out a chimney or a wall vent.
When the refrigerator came along, it seems that, over time, the vents were boarded up and the California Cooler was all but forgotten. Today, if you walk the streets of my hometown, Berkeley, where most of the houses were built in the 1920's, you will see many homes, and even apartment buildings, with the exterior vestiges of these vents."