Horizontal Flow

By Anne Fonda

Horizontal flow in HVAC refers to the air handler or furnace airflow direction. Rather than the traditional upright furnace with an upflow air direction, a horizontal flow furnace appears to be lying on its side. Air flows in one end, passes over the heat exchanger, and flows out the other end into your ductwork.

Horizontal flow furnaces are most common in an attic or crawl space where height restrictions prohibit a vertical installation. The gas furnace itself is the same as an upright furnace with an upflow or downflow. The installation configuration of a horizontal flow gas furnace is the only difference.

Unless you are building a new home, the most cost-effective furnace air flow configuration for furnace replacement is the one that already exists. Be aware that not all furnaces and air handlers are designed for a horizontal installation. Look for furnaces that are described as multi-positional or multipoise.

Work with an HVAC professional to find the best furnace for your home and your budget. Contact your local American Standard dealer today for product recommendations.

A Content Writer with Trane Technologies, Anne Fonda researches topics and writes for Trane® and associated residential HVAC brands. She works in collaboration with Trane Technologies subject matter experts, offering easy-to-understand, informative content on complex topics. Her goal is to help consumers make informed decisions on the products and services they need. 

She has written for HVAC and other service provider websites for over 16 years. Before transitioning to web content writing, Anne had a 14-year stint as an award-winning journalist. She graduated cum laude from the University of Missouri-Columbia School of Journalism. When she’s not working, Anne enjoys playing word games, reading, gardening, spending time with family, and visiting gardens and museums.

Expert review by John Kim, Senior Product Manager, Furnaces