What type of furnace is designed for horizontal installation?

The type of furnace specifically designed for horizontal installation is a horizontal furnace. This configuration is necessary in certain settings where vertical space is limited, such as in low-ceiling basements or attics. Horizontal furnaces are engineered to operate effectively in this orientation, allowing for proper airflow and combustion.

This choice stands out because horizontal furnaces have specific components and designs that accommodate their positioning, unlike high-efficiency or condensing furnaces, which can be installed vertically or horizontally but are not explicitly defined by the orientation. Similarly, old-fashioned furnaces may not cater to modern installation needs and requirements. Therefore, the distinction of horizontal installation is clearly addressed by identifying a furnace specifically categorized as horizontal.