What is a furnace with a vertical air flow through the heat exchanger and the blower compartment beneath the heat exchanger called?

A furnace with a vertical air flow through the heat exchanger and the blower compartment located beneath the heat exchanger is typically called a "downflow furnace." This design allows air to be drawn in from the top, heated as it passes through the heat exchanger, and then expelled from the bottom into the living space. Downflow furnaces are commonly used in applications where the furnace is installed in a basement or crawl space.