What type of residential furnace has the supply air coming out from the top and the return in at the bottom?

The type of residential furnace that features supply air exiting from the top and return air entering from the bottom is known as an upflow furnace. This design is typically used in situations where the furnace is located in a basement or a crawl space, allowing for efficient circulation of heated air upwards into the living areas of the home.

The upflow configuration takes advantage of the natural rise of warm air, ensuring that the heated air moves efficiently through the ductwork and into the various rooms, enhancing comfort and efficiency in heating. This design is beneficial for heating large spaces as it allows for better distribution of heat throughout the home.

In contrast, other furnace types have distinct configurations. A lowboy furnace usually has a horizontal orientation but is designed for lower height applications. Counterflow furnaces pull air in from the top and expel it at the bottom, which is the opposite of the upflow design. Horizontal furnaces are oriented to accommodate space restrictions, typically installed in attics or tight spaces, and their airflow direction can vary based on the installation. Each design serves specific purposes depending on the architectural layout and heating requirements of a home.