and now, NASCAR Racing Sponsor
What the configuration means
Furnaces and air handlers move air in a set direction. The configuration has to match how your equipment is positioned and where the ductwork connects, or it will not work with your setup.
| Configuration | Air flows | Typical location |
|---|---|---|
| Upflow | In the bottom, out the top | Basement or a closet with ducts above |
| Downflow | In the top, out the bottom | Attic, or a closet with ducts below |
| Horizontal | In one side, out the other | Crawlspace or a low attic, lying on its side |
How to know which you have
Where is the equipment
A basement furnace blowing up into the home is upflow. An attic unit blowing down into the living space is downflow. A unit lying flat in a crawlspace or low attic is horizontal.
Multi-position units
Many modern air handlers and some furnaces are multi-position, meaning they can be set up for more than one orientation. That simplifies matching, but you still confirm the configuration for your install.
Why it matters
Order the wrong configuration and the unit will not connect correctly to your ductwork or supply air the right way. When you replace a furnace or air handler, match the airflow direction of the old one unless your installer is changing the layout.
Shop furnaces and air handlers
Browse configurations that match your setup.
Common configuration questions
How do I know if I need upflow or downflow?
What is a multi-position furnace?
Can I replace a downflow with an upflow?
Is horizontal less efficient?
25 years sizing and shipping HVAC systems to homeowners and contractors.