A fan coil unit, or FCU, uses a coil and fan to heat or cool a room without ductwork, making it suitable for individual room temperature control.

Fan Energy Rating (FER) is a government-regulated standard for energy efficiency in residential furnace fans and gas-packaged units.

A furnace is a whole-home heating solution that burns fuel, like natural gas or propane, to generate heat, which is distributed via ductwork.