Horizontal Flow - a HVAC Unit flow style, which refers to the direction of the airflow out of the unit. In HVAC sysytem with horizontal flow the furnace or air handler unit seems to be laying on its side and the airflow flows in from one side and then exhausts it out at the other side. This type of system is most common in attics and craw spaces.
Pros & Cons of a Horizontal Flow HVAC System
The horizontal flow directionality means that you can install the unit virtually anywhere in your home unlike a downflow unit, which needs to sit in the attic, or an upflow, which is typically in the basement.
The location versatility can save you costs during the AC installation process because you won't need bracing added the way a downflow unit does. Service calls will also come in cheaper since the HVAC technician won't have to try and crawl into an awkward, hard to access place to fix the Air Conditioning unit.
The directionality of your unit can affect both your heating and cooling capabilities. Using a horizontal flow unit you might not see the same level of efficiency savings as when using an upflow unit, but you also won't see the type of efficiency losses as when using downflow unit wich is trying to push the air against its natural direction either.
The most common terms used to describe the air flow configuration are: upflow, downflow, and horizontal.
Many horizontal flow systems will reside in attics or crawl spaces that don’t have space for a traditional upflow or downflow system.
Choosing the right type of flow for your home's setup and needs can maximize efficiency while minimizing energy costs.