An "air handler" is a system or device that circulates and distributes air within a building. It helps control the temperature, ventilation, and filtration of the air to ensure a comfortable and healthy indoor environment. Full definition
Provide installation flexibility with the capability to be installed with a remote air handler for whole house heating and cooling. (waterfurnace.com)
It got there because the basement is cool, especially when the HVAC air handler is on in the summer time. (treehugger.com)
For example, if you place the 500RO11 Outdoor Split just outside your home you can house the 5 Series SAH Air Handler in the attic or crawlspace to utilize your space effectively. (waterfurnace.com)